Electric toothbrush and method for operating an electric toothbrush

ABSTRACT

An electric toothbrush that detects plaque on the teeth, ensures accurate plaque detection, and performs cleaning of plaque. The electric toothbrush may include a body having a gripping part and a stem with a brush unit detachably coupled to the body. The electric toothbrush may include a light emitting element for emitting light onto the tooth and a light receiving element for receiving light that reflects off of the tooth. A controller may be included to determine an amount of plaque on the tooth based on the amount of reflected light detected. The electric toothbrush may also include a fluid dispensing system that dispenses fluid based on the amount of reflected light detected. In some aspects, the electric toothbrush may operate in multiple oscillation modes, and it may only dispense fluid in some of the modes but not all of the modes.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority under 35 U.S.C. § 119 toJapanese Patent Application No. 2015-119561, filed Jun. 12, 2015,Japanese Patent Application No. 2015-119562, filed Jun. 12, 2015, andJapanese Patent Application No. 2015-122897, filed Jun. 18, 2015, thedisclosures of which are incorporated herein by reference.

BACKGROUND

The present invention relates to an electric toothbrush and method foroperating an electric toothbrush. A type of electric toothbrush thatcarries out tooth brushing by applying a brush oscillating at high speedto teeth is known. It has been proposed to provide on a brush unit ofsuch electric toothbrush means for sensing a cavity of a tooth as wellas plaque and tartar deposited on the tooth. Some electric toothbrushesare known that irradiate light against a tooth and detect the lightreflected from the tooth using a light sensor to thereby sense a stain,such as plaque and tartar, on the tooth. These electric toothbrushes areused while toothpaste is on the brush unit. However, while toothpaste ison the surface of a tooth, light cannot be applied to the tooth to senseplaque and tartar deposited on the tooth. Thus, a need exists for anelectric toothbrush that can improve the sensing accuracy of a stain ona tooth and optimize plaque removal.

BRIEF SUMMARY

The present invention may be directed, in one aspect, to an electrictoothbrush comprising: a driving unit for driving a brush unit mountedon a main body; a light emitting module for emitting light from thebrush unit; a reflected light detecting module for detecting reflectedlight of light emitted from the light emitting module; a stain sensingmodule for sensing a stain amount of a tooth based on an amount of thereflected light detected by the reflected light detecting module; afluid spraying module for spraying fluid from the brush unit; and afluid spray control unit for controlling spray timing of the fluid basedon the amount of the reflected light detected by the reflected lightdetecting module.

In one aspect, the invention may be directed to a method for operatingan electric toothbrush having a drive module for driving a brush unitmounted on a main body, including: a light emitting step for emittinglight from the brush unit; a reflected light detecting step fordetecting reflected light of the emitted light; a stain sensing step forsensing a stain amount of a tooth based on reflected light detected bythe reflected light detecting step; a fluid spray step for sprayingfluid from the brush unit; and a fluid spray control step forcontrolling the spray timing of the fluid based on the amount ofreflected light detected by the reflected light detecting step.

In another aspect, the invention may be an electric toothbrushcomprising: a body comprising a gripping part and a stem extending fromthe gripping part; a brush unit detachably coupled to the body, thebrush unit having an outer surface including a front surface having aplurality of tooth cleaning elements extending therefrom; a motorlocated within the body and operably coupled to an eccentric shaft tooscillate the brush unit; a light emitting element configured to emitlight from the brush unit; a light receiving element configured toreceive reflected light of the light emitted from the light emittingelement; a fluid dispensing system comprising a reservoir for storing afluid, a fluid conduit extending from the reservoir to an outlet, and atleast one of a pump and a valve for controlling dispensing of the fluidfrom the reservoir; a controller operably coupled to the motor, thelight emitting element, the light receiving element, and the fluiddispensing system, the controller receiving data indicative of an amountof the reflected light received by the light receiving element; andwherein the controller controls operation of the fluid dispensing systembased on the amount of the reflected light detected by the lightreceiving element.

In yet another aspect, the invention may be an electric toothbrushcomprising: a body comprising a gripping part and a stem extending fromthe gripping part, the stem having an internal cavity, a first windowthat provides visibility from an outer surface of the stem into theinternal cavity of the stem, and a first opening extending from theouter surface of the stem to the internal cavity of the stem; a brushunit detachably coupled to the body, the brush unit having an outersurface including a front surface having a plurality of tooth cleaningelements extending therefrom, a second window that provides visibilityinto an interior cavity of the brush unit, and a second openingextending from the outer surface of the brush unit to the interiorcavity of the brush unit, the brush unit coupled to the body so that thefirst and second windows and the first and second openings are aligned;a motor located within the body and operably coupled to a controller tocontrol operation of the motor; an eccentric shaft operably coupled tothe motor and located at least partially within the internal cavity ofthe stem, a weight operably coupled to the eccentric shaft to oscillatethe brush unit; a light emitting element located within the internalcavity of the stem and aligned with the first and second windows so thatlight emitted from the light emitting element passes through the firstand second windows, the light emitting element operably coupled to thecontroller; a light receiving element located within the internal cavityof the stem and aligned with the first and second windows so thatreflected light passes through the first and second windows to the lightreceiving element, the light receiving element operably coupled to thecontroller; a fluid dispensing system comprising a reservoir for storinga fluid, a fluid conduit extending from the reservoir to the firstopening in the stem, and at least one of a pump and a valve operablycoupled to the controller for controlling dispensing of the fluid fromthe reservoir; and wherein the controller controls operation of thefluid dispensing system based on an amount of the reflected lightdetected by the light receiving element.

In still another aspect, the invention may be a method for operating anelectric toothbrush having a drive module for driving a brush unitmounted on a main body, the method comprising: emitting light from thebrush unit towards a tooth; detecting reflected light of the emittedlight that reflects off of the tooth; and spraying fluid from the brushunit based on an amount of the reflected light detected.

In a further aspect, the invention may be an electric toothbrushcomprising: a driving portion that performs a first driving thatoscillates a brush unit in a first direction that is a pressingdirection of a plurality of tooth cleaning elements provided on thebrush unit and a second driving that oscillates the brush unit in asecond direction that is different from the first direction; a fluidspraying unit that sprays a fluid from the brush unit; and wherein thedriving portion carries out the first driving while the fluid is beingsprayed from the fluid spraying unit.

In a still further aspect, the invention may be a method for electrictoothbrush operation comprising: a driving step that performs a firstdriving that oscillates a brush unit coupled to a main body portion ofthe electric toothbrush in a first direction that is a pressingdirection of a plurality of tooth cleaning elements provided on thebrush unit and a second driving that oscillates the brush unit in asecond direction that is different from the first direction; a fluidspraying step that sprays a fluid from the brush unit; and wherein thedriving step carries out the first driving while the fluid is beingsprayed according to the fluid spraying step.

In another aspect, the invention may be an electric toothbrushcomprising: a body comprising a gripping part and a stem extending fromthe gripping part; a brush unit detachably coupled to the body andhaving a plurality of tooth cleaning elements extending therefrom; adrive assembly located in the body and configured to oscillate the brushunit, wherein the drive assembly is operably coupled to a controller toalternate operation of the drive assembly between at least: (1) a firstmode wherein the drive assembly oscillates the brush unit in a firstdirection; and (2) a second mode wherein the drive assembly oscillatesthe brush unit in a second direction that is different than the firstdirection; a fluid dispensing system for dispensing a fluid, the fluiddispensing system operably coupled to the controller to controloperation of the fluid dispensing system; and wherein when the fluid isbeing dispensed by the fluid dispensing system, the drive assembly onlyoperates in the first mode.

In one aspect, the invention may be an electric toothbrush comprising: adrive module for selectively performing a first drive for oscillating abrush unit installed on a main body in a first direction that is apressing direction of a plurality of tooth cleaning elements provided onthe brush unit and a second drive for oscillating the brush unit in asecond direction that is different from the first direction; a lightemitting module for emitting light from the brush unit; a reflectedlight detector for detecting reflected light of the light emitted fromthe light emitting module; a plaque detector for detecting plaque basedon the reflected light detected by the reflected light detector; aliquid spray part for spraying liquid from a portion of the brush unitthat is surrounded by the plurality of tooth cleaning elements; and aliquid spray controller for controlling a spray timing of the liquid;wherein the liquid spray controller sprays the liquid when the amount ofplaque detected by the plaque detector exceeds a threshold; and whereinthe drive module stops the first drive and performs only the seconddrive while the liquid is being sprayed.

In still another aspect, the invention may be an operating method of anelectric toothbrush comprising a light emitting module for emittinglight from a brush unit having a plurality of tooth cleaning elementsinstalled on the electric toothbrush, a reflected light detector fordetecting reflected light of the light emitted from the light emittingmodule, and a liquid spray part for spraying liquid from a portionsurrounded by the plurality of tooth cleaning elements from the brushunit, the method comprising: a drive step for selectively performing afirst drive for oscillating the brush unit installed on a main body in afirst direction, which is the direction of pressing the plurality oftooth cleaning elements provided on the brush unit and a second drivefor oscillating the brush unit in a second direction, which is differentfrom the first direction; a plaque detection step for detecting plaquebased on the reflected light detected by the reflected light detector;and a liquid spray control step for spraying the liquid when the amountof plaque detected during the plaque detection step exceeds a threshold;and wherein within the drive step, the first drive is stopped and onlythe second drive is performed while the liquid is being sprayed.

In yet another aspect, the invention may be an electric toothbrushcomprising: a body comprising a gripping part and a stem extending fromthe gripping part; a brush unit detachably coupled to the body andhaving a plurality of tooth cleaning elements extending therefrom; adrive assembly located in the body and configured to oscillate the brushunit, wherein the drive assembly is operably coupled to a controller toalternate operation of the drive assembly between at least: (1) a firstmode wherein the drive assembly oscillates the brush unit in a firstdirection; and (2) a second mode wherein the drive assembly oscillatesthe brush unit in a second direction that is different than the firstdirection; a light emitting element operably coupled to the controllerand configured to emit light from the brush unit; a light receivingelement operably coupled to the controller and configured to receivereflected light of the light emitted from the light emitting element,the controller determining an amount of plaque based on an amount of thereflected light received by the light receiving element; and a fluiddispensing system for dispensing a fluid, the fluid dispensing systemoperably coupled to the controller, the controller initiating the fluiddispensing system to dispense the fluid when the amount of plaqueexceeds a threshold; and wherein when the fluid is being dispensed bythe fluid dispensing system, the drive assembly only operates in thesecond mode.

In still another aspect, the invention may be an electric toothbrushcomprising: a body comprising a gripping part and a stem extending fromthe gripping part; a brush unit detachably coupled to the body andhaving a plurality of tooth cleaning elements extending therefrom; adrive assembly located in the body and configured to oscillate the brushunit, wherein the drive assembly is operably coupled to a controller toalternate operation of the drive assembly between at least: (1) a firstmode wherein the drive assembly oscillates the brush unit in a firstdirection; and (2) a second mode wherein the drive assembly oscillatesthe brush unit in a second direction that is different than the firstdirection; a light emitting element operably coupled to the controllerand configured to emit light from the brush unit; a light receivingelement operably coupled to the controller and configured to receivereflected light of the light emitted from the light emitting element,the controller determining an amount of plaque based on an amount of thereflected light received by the light receiving element; and a fluiddispensing system for dispensing a fluid, the fluid dispensing systemcomprising a tank for storing the fluid, the fluid dispensing systemoperably coupled to the controller, wherein the controller is configuredto identify the fluid as a type of fluid and initiate the fluiddispensing system to dispense the fluid when the amount of plaqueexceeds a threshold; and wherein when the fluid is being dispensed bythe fluid dispensing system and the fluid is water, the drive assemblyonly operates in the first mode; and wherein when the fluid is beingdispensed by the fluid dispensing system and the fluid is not water, thedrive assembly only operates in the second mode.

Further areas of applicability of the present invention will becomeapparent from the detailed description provided hereinafter. It shouldbe understood that the detailed description and specific examples, whileindicating the preferred embodiment of the invention, are intended forpurposes of illustration only and are not intended to limit the scope ofthe invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become more fully understood from thedetailed description and the accompanying drawings, wherein:

FIG. 1 is a top view of an electric toothbrush in accordance with afirst embodiment of the present invention.

FIG. 2 is a schematic cross sectional view taken along line A-A in FIG.1.

FIG. 3 is a block diagram illustrating an internal configuration of amain body of the electric toothbrush of FIG. 1.

FIG. 4 is a flowchart for describing the operation of the electrictoothbrush of FIG. 1.

FIG. 5 is a top view of an electric toothbrush in accordance with asecond embodiment of the present invention.

FIG. 6 is a flowchart for describing an operation of the electrictoothbrush of FIG. 5.

FIG. 7 is a top view of an electric toothbrush in accordance with athird embodiment of the present invention.

FIG. 8 is a top view of an electric toothbrush in accordance with afourth embodiment of the present invention.

FIG. 9 is a top view an electric toothbrush in accordance with a fifthembodiment of the present invention.

FIG. 10 is a top view an electric toothbrush in accordance with a sixthembodiment of the present invention.

FIG. 11 is a cross-sectional view taken along line A-A of FIG. 10.

FIG. 12 is a block diagram showing the internal configuration of a mainbody of the electric toothbrush of FIG. 10.

FIG. 13 is a flow chart for describing the operation of the electrictoothbrush of FIG. 10.

DETAILED DESCRIPTION

The following description of the preferred embodiment(s) is merelyexemplary in nature and is in no way intended to limit the invention,its application, or uses.

The description of illustrative embodiments according to principles ofthe present invention is intended to be read in connection with theaccompanying drawings, which are to be considered part of the entirewritten description. In the description of embodiments of the inventiondisclosed herein, any reference to direction or orientation is merelyintended for convenience of description and is not intended in any wayto limit the scope of the present invention. Relative terms such as“lower,” “upper,” “horizontal,” “vertical,” “above,” “below,” “up,”“down,” “top,” and “bottom” as well as derivatives thereof (e.g.,“horizontally,” “downwardly,” “upwardly,” etc.) should be construed torefer to the orientation as then described or as shown in the drawingunder discussion. These relative terms are for convenience ofdescription only and do not require that the apparatus be constructed oroperated in a particular orientation unless explicitly indicated assuch. Terms such as “attached,” “affixed,” “connected,” “coupled,”“interconnected,” and similar refer to a relationship wherein structuresare secured or attached to one another either directly or indirectlythrough intervening structures, as well as both movable or rigidattachments or relationships, unless expressly described otherwise.Moreover, the features and benefits of the invention are illustrated byreference to the exemplified embodiments. Accordingly, the inventionexpressly should not be limited to such exemplary embodimentsillustrating some possible non-limiting combination of features that mayexist alone or in other combinations of features; the scope of theinvention being defined by the claims appended hereto.

As used throughout, ranges are used as shorthand for describing each andevery value that is within the range. Any value within the range can beselected as the terminus of the range. In addition, all references citedherein are hereby incorporated by referenced in their entireties. In theevent of a conflict in a definition in the present disclosure and thatof a cited reference, the present disclosure controls.

Referring to FIGS. 1 and 2 concurrently, an electric toothbrush 100(also referred to herein as an oral care implement or a poweredtoothbrush in some embodiments) will be described in accordance with anembodiment of the present invention. FIG. 1 is a planar viewillustrating a schematic configuration of the electric toothbrush 100viewed from the brush pressing direction (the direction that a userpresses onto tooth cleaning elements during use), for describing oneembodiment of the present invention. FIG. 2 is a cross-sectional viewtaken along line A-A of FIG. 1.

The electric toothbrush 100 includes a gripping part 10 that includes abattery and an electric control system therein, as well as a main bodyhaving a stem 11 fixed to the gripping part 10, and a brush unit 20 thatcan be detached from the stem 11. The stem 11 extends from the grippingpart 10 and forms the portion of the electric toothbrush 100 that thebrush unit 20 may be coupled to. Specifically, the brush unit 20comprises a cylindrical housing that defines an interior cavity 43having a closed distal end 20 a. The brush unit 20 may be coupled to thestem 11 by inserting the stem 11 into the interior cavity 43 of thebrush unit. The brush unit 20 may be repetitively coupled to anddetached from the stem 11 as necessary or desired. The brush unit 20 andthe stem 11 may also include corresponding structures that facilitatelocking the brush unit 20 to the stem 11 (a boss and a correspondingnotch, an indent and a corresponding detent, or the like). Thus, thegripping part 10 and the stem 11 may be reused with different brushunits 20 having different structural arrangements to achieve differentpurposes. Furthermore, the brush units 20 may be replaced when the toothcleaning elements thereon are worn or splayed over time. This saves auser costs because the portion of the electric toothbrush 100 thatincludes the circuitry may be reused while the brush unit 20 which is asimple and cheap component may be replaced. The brush unit 20 may bereferred to herein and in the art as a refill head.

The brush unit 20 includes a front surface 41 and an opposite rearsurface 42. In certain embodiments the brush unit 20 may comprise a headportion and a sleeve portion. Furthermore, the brush unit 20 includes aplurality of tooth cleaning elements 22 extending from the front surface41 (particularly of the head portion). The plurality of tooth cleaningelements 22 are depicted in various aligned columns and rows, althoughthe invention is not to be so limited. The number, pattern,configuration, and structure of the tooth cleaning elements 22 are notto be limited by the exemplary embodiments illustrated in allembodiments. In certain embodiments, the tooth cleaning elements 22 areformed by a plurality of bristles that are bundled together into tuftsthat are then coupled to the head portion of the brush unit 20. Thetooth cleaning elements 22 may be coupled to the head using stapletechnology, anchor-free tufting technologies, in-mold tuftingtechnologies, or any other technology now known or later discovered. Thetooth cleaning elements 22 may include bristles alone, bristles incombination with lamella formed of an elastomeric material, onlybristles formed of an elastomeric material, or the like. The inventionis not to be particularly limited by the specific details of thebristles unless specifically claimed as such. As discussed above, incertain embodiments the brush unit 20 may be detachable from the stem 11and replaceable as needed when the tooth cleaning elements 22 thereonbecome frayed from use.

The brush unit 20 also includes a hole 21 that permits a liquid to besprayed therethrough and a transparent window 23 that permits light tobe emitted therethrough. Specifically, in the exemplified embodiment thehole 21 is formed into the front surface 41 of the brush unit 20 andforms a passageway from the ambient environment into the interior cavity43. Furthermore, the hole 21 is fluidly coupled to a fluid conduit 27 sothat fluid can flow through the fluid conduit 27 and out the hole 21 asdescribed in more detail below. In the exemplified embodiment the hole21 is positioned in a central region of the brush unit 20 surrounded bythe tooth cleaning elements 22. However, the position of the hole 21 isan example, and is not limited to the position illustrated in FIG. 1.Thus, the hole 21 may be located at other positions along the brush unit20, including other positions on the front surface 41 of the brush unit20 and even on the rear surface 42 of the brush unit 20 in otherembodiments. The hole 21 may be disposed so that the liquid can beemitted in the direction the tooth cleaning elements 22 extend from thebrush unit 20 (i.e., perpendicular to the front surface 41 of the brushunit 20). Alternatively, the hole 21 may be arranged so that the liquidcan be sprayed at an oblique angle relative to the front surface 41 ofthe brush unit 20.

In the exemplified embodiment, the brush unit 20 includes a second hole44 for retaining the transparent window 23. Specifically, thetransparent window 23 is formed by fitting a translucent member such asa transparent resin or transparent glass to the second hole 44 providedin the housing of the brush unit 20. In the exemplified embodiment, thetransparent window 23 is located on the front surface 41 of the brushunit 20 (i.e., the same surface from which the tooth cleaning elements22 extend). Furthermore, in the exemplified embodiment the transparentwindow 23 is located along a distal portion of the brush unit 20.Specifically, in the exemplified embodiment the tooth cleaning elements22 form a bristle field, and the transparent window 23 is locatedexternal to the bristle field and between the bristle field and adistal-most end 45 of the brush unit 20. Of course, the invention is notto be so limited in all embodiments and the transparent window 23 may belocated within the field of tooth cleaning elements 22 or at any otherdesired location along the brush unit 20 in other embodiments. Thus, theinvention is not to be particularly limited by the position of thetransparent window 23 unless specifically claimed as such. Statedanother way, the position of the transparent window 23 is an example,and is not limited to the position illustrated in FIG. 1.

As will be described in more detail below, the window 23 is positionedadjacent to a light source so that light from the light source may emitthrough the window 23. The light source and the window 23 may bedisposed so that the light can be emitted in the direction the toothcleaning elements 22 extend from the front surface 41 of the brush unit20 (i.e., perpendicular to the front surface 41 of the brush unit 20).In other embodiments, the window 23 may be disposed so that the lightcan be emitted in a direction that is at an oblique angle relative tothe front surface 41 of the brush unit 20.

The stem 11 is configured with a cylindrical housing in which the tipend (end of the opposite side of the gripping part 10 side) is closed.The stem 11 includes a bearing 12 formed on the tip end therein, aneccentric shaft 13 in which one end is inserted into the bearing 12, aweight 14, substrate 15, a light emitting element 24 formed on thesubstrate 15, a light receiving element 25 and a light receiving element26 (see FIG. 1) formed on the substrate 15, a transparent window 23 aprovided in the housing, and the fluid conduit 27. In certainembodiments, the light emitting element 24 and the light receivingelements 25, 26, alone or in combination with a controller, may becollectively referred to as a tooth stain or plaque detection system.

The gripping part 10 includes a valve 28 connected with the fluidconduit 27 extending from inside the stem 11, a pump 29 connected to thevalve 28, a tank 30 connected to the pump 29, a liquid supply opening 31for pouring liquid in the tank 30, a cap 32 for closing the liquidsupply opening 31, and a motor M linked with the eccentric shaft 13 inthe stem 11. Although the exemplified embodiment illustrates the tank30, in other embodiments the tank 30 may be omitted and the fluidconduit 27 may be coupled directly to a source of fluid rather than tothe tank 30. The tank 30, the fluid conduit 27, the pump 29, and/or thevalve 28 may be collectively referred to herein as a fluid spraying unitor a fluid dispensing system.

The other end of the eccentric shaft 13 is linked to a rotary shaft ofthe motor M built in the gripping part 10. By rotating the rotary shaftof the motor M, the eccentric shaft 13 rotates. The weight 14 is fixedto the eccentric shaft 13 in the vicinity of the bearing 12. Due to thisweight 14, the center of gravity of the eccentric shaft 13 is shiftedfrom the center of rotation. Note that a minute clearance is providedbetween the eccentric shaft 13 and the bearing 12. Although theeccentric shaft 13 rotates along with the rotation of the rotary shaftof the motor M, since the center of gravity of the eccentric shaft 13 isshifted due to the weight 14, a motion of turning about the center ofrotation is carried out. Thus, the entire eccentric shaft 13 bends, andthe stem 11 as well as the brush unit 20 installed therein, oscillate ata high speed. Specifically, when the motor M is powered on and rotating,the eccentric shaft 13 rotates and due to the offset nature of theweight 14 (also referred to herein as an eccentric), the brush unit 20oscillates. Thus, powering the motor M results in the brush unit 20oscillating, which enhances cleaning of a user's teeth. The combinationof the motor M, the eccentric shaft 13, and the weight 14 may bereferred to collectively herein as a drive unit or a drive assembly insome embodiments. Thus, the components that work together to createoscillation in the brush unit 20 may be referred to as the drive unit ordrive assembly.

Thus, in cases of the drive principle in which the brush unit 20 isoscillated due to the turning motion of the eccentric shaft 13, thebrush unit 20 may oscillate two-dimensionally in a plane perpendicular(parallel to the pressing direction of the tooth cleaning elements 22)to the rotary shaft of the motor M. Note that, the pressing direction ofthe tooth cleaning elements 22 coincides with the direction in whicheach tooth cleaning elements 22 is extending. Thus, the pressingdirection of the tooth cleaning elements 22 is the directionperpendicular to the front surface 41 of the brush unit 20.

With the electric toothbrush 100, the entirety of the oscillating part(stem 11 and brush unit 20) has a resonance point (resonance frequency),and can switch operations (or modes) between a first operation or modein which the stem 11 and brush unit 20 oscillate in the pressingdirection of the tooth cleaning elements 22 and a second operation ormode in which the stem 11 and brush unit 20 oscillate in a directionthat is different from the direction of oscillation in the firstoperation or mode. Thus, in the second operation or mode the brush unit20 may oscillate in a direction that intersects the pressing directionof the tooth cleaning elements 22. The second operation or mode may bein a plane perpendicular to the rotary shaft of the motor M (i.e.,side-to-side in a direction of the lateral sides of the brush unit 20)or in a plane parallel to the rotary shaft of the motor M (in aback-and-forth direction in a direction towards and away from thedistal-most end 45 of the brush unit 20. In some embodiments, the modeor operation of the electric toothbrush 100 may be changed between thefirst and second operations/modes by controlling the rotary speed of themotor M, although other techniques for alternating between the modes mayalso be used.

As illustrated in FIG. 2, the stem 11 comprises a housing 46 having aninner surface 47 that defines a cavity 48. The shaft 13 is positionedwithin the cavity 48 of the stem 11. Furthermore, the stem 11 comprisesa transparent window 23 a in a location facing or adjacent to thetransparent window 23 of the housing of the brush unit 20. Thetransparent window 23 a of the stem 11 may be formed of substantiallythe same size as the transparent window 23 of the brush unit 20. Thetransparent windows 23, 23 a cooperate to permit light from the lightemitting element 24 to pass through both of the transparent windows 23,23 a so that the light may be emitted from the electric toothbrush 100to a user's teeth and other oral surfaces. The transparent window 23 ais formed by fitting a translucent member such as a transparent resin ortransparent glass and the like in a hole formed into the housing 46 ofthe stem 11.

The light emitting element 24 illustrated in FIG. 1, the light receivingelement 25, and the light receiving element 26, are disposed on thesubstrate 15 in a position opposite the transparent window 23 a. Thus,the light emitting element 24 and the light receiving elements 25, 26are visible through, and are capable of emitting light and receivinglight, respectively, through the windows 23, 23 a. The light emittingelement 24 and the windows 23, 23 a are generally positioned andoriented to permit light from the light emitting element 24 to beemitted towards or onto a user's teeth. The light receiving elements 25,26 and the windows 23, 23 a are generally positioned and oriented topermit light that is reflected off of the teeth to be emitted back tothe light receiving elements 25, 26. This functionality will bedescribed in more detail below.

Although the above states that the light receiving elements 25, 26 areconfigured to receive light that is reflected off of the teeth, itshould be appreciated that the light is not always reflected off of theteeth as that term is commonly defined. Rather, in certain instances thelight may be fluoresced by the teeth. Specifically, reflectance is whenlight is not absorbed, but is redirected back and fluorescence is whenlight is absorbed, and then re-emitted at a different wavelength. Thus,in certain instances the light emitted at the teeth is fluoresced backtowards the light receiving elements 25, 26 rather than being reflectedback towards the light receiving elements 25, 26. Thus, as used herein,the term reflect will include solely reflectance, solely fluorescence,and combinations of reflectance and fluorescence. Each iteration of theterm “reflect,” “reflected,” “reflectance,” or similar in thespecification and the claims should be understood to include light thatis reflected and/or fluoresced.

The light emitting element 24 may comprise an LED (Light Emitted Diode)or a laser diode and the like. The light emitting element 24 is not tobe limited by any particular type of light source and the above aremerely non-limiting examples. The light emitting element 24 may in someembodiments emit a light in the blue wavelength range (hereinafterreferred to as B light). This may be desirable because B light isgenerally understood to be capable of sensing a stain (plaque, tartarand the like) on teeth. The B light emitted from the light emittingelement 24 passes through the transparent window 23 a and thetransparent window 23, and is emitted outside of the brush unit 20 andonto the user's teeth during use of the electric toothbrush 10. Thelight emitting element 24, the transparent window 23 a and thetransparent window 23 may collectively function as a light emittingmodule for emitting light from the brush unit 20.

The light receiving element 25 and the light receiving element 26 areconfigured respectively by a photoelectric conversion element such as aphoto diode that converts the light to an electrical signal. The lightreceiving element 25 is configured to detect light in the red wavelengthrange (hereinafter referred to as R light). Furthermore, the lightreceiving element 25 is configured by a photoelectric conversion elementto output a signal corresponding to the amount of R light detected. Thissignal may be received by a controller for further processing. The lightreceiving element 25 is configured as a combination of a color filterthat transmits R light and a photo diode that has sensitivity in visiblelight, or as a photo diode and the like that can only detect R light.

The light receiving element 26 is configured to detect light in thegreen wavelength range (hereinafter referred to as G light).Furthermore, the light receiving element 26 is configured by aphotoelectric conversion element to output a signal corresponding to theamount of G light detected. This signal may be received by a controllerfor further processing. The light receiving element 26 is configured asa combination of a color filter that transmits G light and a photo diodethat has sensitivity in visible light, or as a photo diode and the likethat can only detect G light. The light receiving elements 25, 26 aresimilar except with respect to the wavelength of light receive thereby.

During use, the light emitting element 24 emits B light through thewindows 23, 23 a and onto the user's teeth. When the B light contactsplaque adhering to the tooth, the R light becomes excited in the plaque.In other words, when the B light contacts plaque (i.e., plaque adheredto the tooth), R light is generated as the reflected light of the Blight. In certain embodiments, the B light is absorbed by the plaque andre-emitted as the R light (i.e., fluoresced). In addition, when the Blight contacts a portion of the tooth without plaque (i.e., an exposedportion of the tooth), the G light is added to the reflected portion ofthe B light in this portion. In certain embodiments, the B light isabsorbed by the exposed portion of the tooth and re-emitted as G light(i.e., fluoresced). As noted above, the term “reflect” as used hereinincludes reflectance, fluorescence, and combinations thereof. In otherwords, the G light is generated as one part the reflected (orfluoresced) light of the B light. Sated another way, the B light isemitted at the user's tooth or teeth. The B light is then reflected (orfluoresced) from the user's teeth as both R light and G light. Thus, thereflected (or fluoresced) light has an R light component for portions ofthe B light that are reflected (fluoresced) from portions of the tooththat have plaque thereon and a G light component for portions of the Blight that are reflected (fluoresced) from portions of the tooth thathave no plaque thereon (i.e., exposed portions of the tooth).

To state succinctly, the light receiving element 25 is provided fordetecting/receiving R light that is generated when the B light emittedfrom the light emitting element 24 contacts plaque, tartar, or otherstain. The light receiving element 26 is provided for detecting G lightgenerated when the B light emitted from the light emitting element 24contacts an exposed portion of the tooth that is free of plaque, tartar,or other stain. The light receiving element 25 and the light receivingelement 26 function as a reflecting/fluorescing light detecting modulethat detects reflected/fluoresced light of the B light emitted from thelight emitting module. In some embodiments, the light receiving elements25, 26 may be a single light receiving element capable of receiving anddistinguishing between the R light and the G light. Thus, as used hereinthe phrase light receiving element may denote a single light receivingelement that is configured to receive both the R light and the G lightor multiple light receiving elements for separately receiving the Rlight and the G light, respectively.

The substrate 15 may be any type of electrical substrate that canoperably power the light emitting element 24 and the light receivingelements 25, 26. In some embodiments, the substrate 15 may be a flexiblesubstrate, although the invention is not to be so limited in allembodiments and the substrate 15 may be any other type of substrate asdesired. The substrate 15 is electrically connected to the lightemitting element 24, the light receiving element 25 and the lightreceiving element 26. The substrate 15 extends to the inside part of thegripping part 10, and the wiring formed in the substrate 15 iselectrically connected to a controller 50 (see FIG. 3) to be describedlater, that is built into the gripping part 10. In this manner, thecontroller 50 controls operation of the light emitting element 24 andthe light receiving elements 25, 26. Specifically, the controller 50 maycontrol the on/off status of the light emitting element 24 and maypermit the transfer and storage of signals from the light receivingelements 25, 26 regarding amounts of R and G light received tofacilitate other functions of the electric toothbrush 100 describedherein.

The tank 30 forms a reservoir that retains a liquid introduced thereinfrom the liquid supply opening 31. Specifically, a user or manufacturermay open the supply opening 31 by removing the cap 32. The user ormanufacturer may then pour or otherwise introduce a desired liquid intothe tank 30. The liquid may be any desired liquid, including withoutlimitation water, mouthwash, oral care agents that have a desiredbenefit, and the like. The invention is not to be specifically limitedby the particular liquid used unless specifically recited as such in theclaims.

The pump 29 pumps the liquid retained by the tank 30 and supplies it tothe valve 28. Thus, the pump 29 moves the liquid from the tank 30 alonga conduit to the valve 28. The pump 29 may be any type of pump capableof achieving this function. The valve 28 is fluidly coupled to the baseend of the fluid conduit 27 extending from the inside of the stem 11,and controls the supply amount and supply pressure of the liquidsupplied to the fluid conduit 27, as well as the supply timing of theliquid to the fluid conduit 27. In that regard and as discussed in moredetail below with reference to FIG. 3, the valve 28 is operably coupledto the controller 50 so that the controller 50 may provide instructionsto the valve 28 regarding the amount of the liquid to be supplied, thepressure of the liquid to be supplied, and the time period during whichto supply the liquid. This can also be achieved via the pump 29 incommunication with the controller 50 rather than or in addition to thevalve 28.

The fluid conduit 27 is configured as a tubular member that the liquidcan pass through. The fluid conduit 27 may be formed of any desiredmaterial so long as it is impermeable to fluid so that the fluid remainswithin the fluid conduit 27 as it passes therethrough. In the housing 46of the stem 11, a hole 21 a is provided in a portion opposite and facingthe hole 21 of the brush unit 20. Specifically, the hole 21 a in thehousing 46 of the stem 11 is positioned to be in alignment with the hole21 of the brush unit 20 so that the holes 21, 21 a collectively form anoutlet of the fluid dispensing system. The tip end of the fluid conduit27 is fitted in the hole 21 a. The tip end of the fluid conduit 27 maybe pressed against the hole 21, fitted within the hole 21, extendingthrough the hole 21, or the like in various embodiments. With thisconfiguration, the liquid sprayed from the tip end of the fluid conduit27 passes through the hole 21 of the brush unit 20 and is sprayed to theoutside of the brush unit 20. When the electric toothbrush 100 is beingused, the brush unit 20 is within the user's mouth and the fluid beingsprayed from the fluid conduit 27 will be sprayed into the user's mouth.The benefits of this, which include: (1) clearing dentifrice or the likeaway from the teeth to better enable the light from the light emittingelement 24 to contact and be reflected/fluoresced off of the toothsurfaces; and (2) cleaning plaque and tartar from the teeth, will bedescribed in more detail below.

The pump 29, valve 28, fluid conduit 27, hole 21 a, and hole 21collectively function as a fluid spray module or a fluid dispensingsystem for spraying a fluid from the brush unit 20. By changing thecross sectional shape of the hole 21, it is possible to change the spraydirection and spray pattern of the liquid sprayed from the brush unit20. In some embodiments, the spray direction is in the direction inwhich the angle formed with the pressing direction is less than 90degrees, and it is most preferable for the pressing direction (extendingdirection of the tooth cleaning elements 22) of the tooth cleaningelements 22 to be the same.

FIG. 3 is a block diagram illustrating an electrical configuration ofthe main body of the electric toothbrush 100 illustrated in FIG. 1. Themain body of the electric toothbrush 100 includes the motor M, anotification unit 60, the controller 50, the pump 29, and the valve 28.As shown in FIG. 3, each of the valve 28, the pump 29, the notificationunit 60, the motor M, the light emitting element 24, and the lightreceiving elements 25, 26 are operably coupled to the controller 50. Asa result, the controller 50 may communicate with, provide instructionsto, and receive information/signals from each of the aforementionedcomponents. For example, the controller 50 may control when the motor Mpowers on and off and the speed at which the motor M should rotate,which affects the oscillation of the brush unit 20 as described above.Furthermore, the controller 50 may control when the valve 28 and pump 29operate and when the light emitting element 24 emits light. Thecontroller 50 may also receive signals from the light receiving elements25, 26 regarding the amounts of R and G light received by the lightreceiving elements 25, 26. The controller 50 may then process thatinformation/data regarding the R and G light to provide instructionsregarding operation of the valve 28, pump, 29, motor M, and notificationunit 60 as described in more detail below based on the amount of R and Glight received.

The controller 50 functions as a drive module that drives the brush unit20 mounted on the stem 11, by controlling the motor M. The controller 50selectively carries out a first drive (or a first mode) for oscillatingthe brush unit 20 in a first direction, which may be an up-downoscillation in the pressing direction of the tooth cleaning elements 22,and a second drive (or a second mode) for oscillating the brush unit 20in a second direction that is different than the first direction. Thesecond direction may be a direction intersecting the pressing directionof the tooth cleaning elements 22 in the plane perpendicular to therotary shaft of the motor M. Alternatively, the second direction may bea direction intersecting the pressing direction of the tooth cleaningelements 22 in a plane parallel to the rotary shaft of the motor M. Thecontroller 50 may be configured to oscillate the brush unit 20 so thatthe second direction is an arbitrary direction and it may be in a planeperpendicular to the first direction. The controller 50 carries outswitching of the first drive and second drive by changing the rotationalspeed of the rotary shaft of the motor M. Thus, rotation of the rotaryshaft of the motor M at a first speed results in the first drive or modeand rotation of the rotary shaft of the motor at a second speed resultsin the second drive or mode.

During operation of the electric toothbrush 100, the controller 50 mayalternate between carrying out the first and second drives or modes(i.e., causing the brush head 20 to oscillate in the first direction andthe second direction). The controller 50 may alternate between the firstand second drives or modes based on a preset timing (i.e., 10 seconds inthe first drive direction followed by 10 seconds in the second drivedirection), based on a location of the brush unit 20 in the user'smouth, based on a direction of movement of the brush unit 20 within theuser's mouth, or the like. By automatically switching the oscillatingdirection of the brush unit 20, since the bristles of the tooth cleaningelements 22 will contact the teeth and oral surfaces from various angleswith regards to the treatment section, it is possible to obtain a betterplaque removal effect compared to a single direction of brushing. Notethat the driving method of the stem 11 is not particularly limited bythe controller 50. For example, the controller 50 may only carry out thefirst drive (mode), or the controller 50 may only carry out the seconddrive (mode). Thus, in some embodiments the electric toothbrush 100 mayonly be capable of operating in a single mode rather than the dual modeas disclosed herein. Furthermore, in still other embodiments theelectric toothbrush 100 may be configured to operate in more than twodrives or modes.

The controller 50 may also drive the light emitting element 24 via thesubstrate 15, thereby controlling the emitting of the B light from thelight emitting element 24. Thus, the controller 50 may determine theappropriate timing for emitting light from the light emitting element24, as described in more detail below.

The controller 50 carries out a stain sensing process for sensing theamount of stain on a tooth such as plaque and tartar adhered to thetooth, based on reflected light detected by the light receiving element25. The stain sensing process is carried out by a well-known methodbased on the amount of light (detection signal level) of R lightdetected by the light receiving element 25. In this regard, thecontroller 50 functions as a stain sensing module.

The controller 50 controls spray timing of the liquid sprayed from thehole 21, and the spray amount and spray pressure of the liquid, bycontrolling the valve 28 and pump 29 based on the amount of light of Glight detected by the light receiving element 26 and the amount of lightof the R light detected by the light receiving element 25. In thisregard, the controller 50 functions as a fluid spray control unit.

The notification unit 60 comprises a device such as a speaker or a LED(Light Emitting Diode), and notifies the user of the electric toothbrush100 when specific conditions are or are not met. The notification unit60 notifies the user by playing a sound or flashing the LED according toinstructions from the controller 50. For example, in one embodiment thecontent to be notified is the stain amount of the teeth calculated bythe controller 50. For example, the notification unit 60 notifies thestain amount of the tooth by flashing the green LED when the stainamount is very small, and flashing the red LED when the stain amount islarge, and thus supports effective brushing of teeth.

FIG. 4 is a flowchart for describing the operation of the electrictoothbrush 100 illustrated in FIG. 1. When the brushing start operationis performed by the power of the electric toothbrush 100 being turnedon, the controller 50 starts the control for alternating carrying outthe first drive and second drive in accordance with pre-programmedinstructions. Thus, the brush unit 20 pressed against the teeth repeatsalternating oscillating in the first direction and oscillating in thesecond direction, and the plaque adhered to the teeth is removed by thetooth cleaning elements 22. The brush unit 20 may oscillate foridentical time periods in both the first direction and the seconddirection, or it may oscillate longer in one of the first and seconddirections than the other. The specific program that the controller 50follows in instructing oscillation of the brush unit 20 may be modifiedas desired.

In one embodiment, the controller 50 causes the light emitting element24 to emit light at a predetermined timing while alternating between thefirst drive (mode) and the second drive (mode). However, as discussedbelow the controller 50 may only cause the light emitting element 24 toemit light during one of the first drive or the second drive in someembodiments. The B light emitted from the light emitting element 24 isemitted to the outside of the brush unit 20 through the transparentwindow 23 (Step S10). The B light contacts and reflects off of theuser's teeth as R light (when the B light contacts plaque) and G light(when the B light contacts exposed tooth surfaces). The light receivingelements 25, 26 receive the R and G light, respectively, almostimmediately after the light emitting element 24 begins to emit the Blight. Upon receiving the R and G light, the light receiving elements25, 26 transmit signals to the controller indicative of the amounts of Rand G light received.

The controller 50 then determines whether or not the amount of light ofG light detected by the light receiving element 26 (detection signallevel of the light receiving element 26) is less than or equal to afirst threshold TH1 (Step S11). The first threshold is a predeterminedamount of G light and the exact amount of the first threshold may bealtered as desired. If the determination of step S11 is YES (i.e., theamount of G light received by the light receiving element 26 is lessthan or equal to the first threshold TH1), the controller 50 incrementsthe G light non-detection counter by one from the initial value of zero,and it is stored according to the current time in regards to the countvalue (Step S12). If the amount of G light is below the first thresholdTH1, this means that the amount of light being reflected off of thetooth surface is low. This is likely due to dentifrice or some othersubstance in the mouth blocking the B light from reaching and beingreflected off of the tooth surface. However, because the G light may beblocked for only a very brief period of time due to the dentifriceconstantly moving within the user's mouth, it is not immediatelynecessary to clear the path to the tooth surface. Thus, the processcontinues from Step 12 to Step 13, described below.

After step S12, the controller 50 obtains the elapsed time (i.e., theduration of time that the G light is detected as being equal to or lessthan the first threshold) that is the difference between the time storedaccording to the latest count value of the G light non-detectioncounter, and the time stored according to the count value “1” of the Glight non-detection counter, and determines whether or not the elapsedtime is greater than or equal to a second threshold TH2 (Step S13).Thus, the second threshold is a threshold period of time, and it may bepre-determined and pre-set in the controller 50. A user may have theability to change the value of the second threshold in some embodiments.If the amount of G light is less than or equal to the first thresholdTH1 at step S11 and if the time elapsed is greater than or equal to thesecond threshold TH2, it may be determined that insufficient G light isbeing received for a sufficient period of time that the path from thelight emitting element 24 to the tooth should be cleared. Specifically,at this time it may be determined that there is a substance (such astoothpaste) blocking the light from reaching and being reflected off ofthe teeth, which may ultimately affect the ability of the controller 50,in combination with the light receiving elements 25, 26, to determinethe amount of tooth stain. Thus, at this point it may be necessary tospray fluid into the mouth to clear the path from the light emittingelement 24 to the tooth surface and back to the light receiving element26.

When the determination of step S13 is YES (the amount of G light is lessthan or equal to the first threshold TH1 for a period of time that isequal to or greater than the second threshold TH2), the controller 50may operate the valve 28 and the pump 29 to supply water from the tank30 to the fluid conduit 27 at a first supply amount and first pressure(first condition). The controller 50 may then continue to operate thefluid spray control unit to spray the liquid from the tip end of thefluid conduit 27 through the hole 21 and into the user's mouth to clearthe dentifrice or other substance away so that it is not interferingwith the ability of the device to sense stain amounts on the teeth (StepS14).

With the determination of step S13 being YES, it can be assumed to be ina state in which a substance (toothpaste and the like) is adhered to thetooth that blocks light. Thus, by carrying out the process of step S14,the substance adhered to the tooth can be removed, due to the liquidsprayed from the brush unit 20.

After step S14, the controller 50 resets the G light non-detectioncounter (returns the counter value to the initial value of zero), andclears the time stored according to the count value of the G lightnon-detection counter (Step S15). After step S15, the process returns tostep S10, and the B light is emitted again at a predetermined timing.

When the determination of step S11 is NO, this means that the amount ofG light received by the light receiving element 26 is greater than thefirst threshold TH1. This then means that a sufficient amount of the Blight emitted from the light emitting element 24 is contacting the toothsurface and being reflected as the G light. Thus, when the determinationat step S11 is NO, the controller 50 resets the G light non-detectioncounter, and clears the time stored according to the count value of theG light non-detection counter (Step S16). This is done because at thispoint spraying of liquid is not needed to obtain accurate stain sensingbecause a clear path to the tooth already exists. Next, the controller50 determines whether or not the amount of light of R light received byof the light receiving element 25 is less than or equal to a thirdthreshold value TH3 (Step S17). In this embodiment, only when thedetermination of Step S11 or Step S13 is NO does the controller 50 carryout the process of Step S17. Thus, Step S17 (a determination of theamount of R light being received by the light receiving element 25) onlytakes place when the amount of G light is greater than the firstthreshold or when the G light is not less than or equal to the firstthreshold TH1 for a time period greater than the second threshold TH2.

When the determination of step S17 is YES, this means that the amount ofR light received is less than a preset threshold value TH3 such that alimited amount of R light is being detected. At this point, thecontroller 50 increments the R light non-detection counter by one fromthe initial value of zero, and it is stored according to the currenttime in regards to the count value (Step S18).

After Step S18, the controller 50 obtains the elapsed time (same meaningas the duration of state that R light is not detected) that is thedifference between the time stored according to the latest count valueof the R light non-detection counter, and the time stored according tothe count value “1” of the R light non-detection counter, and determineswhether or not the elapsed time is not less than the fourth thresholdTH4 (Step S19). Specifically, this elapsed time is the amount of timethat the R light being detected/received by the light receiving element25 is less than or equal to the third threshold TH3.

When the determination of step S19 is YES (the amount of R light is lessthan the third threshold TH3 for a period of time greater than or equalto the fourth threshold TH4), the controller 50 controls the valve 28and the pump 29, supplies water from the tank 30 to the fluid conduit 27at a second supply amount and a second pressure (second condition), andsprays the liquid from the tip end of the fluid conduit 27 (Step S20)through the hole 21 to the user's teeth oral cavity. In certainembodiments, the first supply amount and the first pressure may be thesame as the second supply amount and the second pressure, and thus thefirst and second conditions may be identical. In other embodiments thefirst and second pressures may be different while the first and secondsupply amounts are the same, the first and second supply amounts may bedifferent while the first and second pressures are the same, or both thefirst and second supply amounts and the first and second pressures maybe different.

With the determination of step S19 being YES, it is assumed to be in astate of either: (1) a first state in which the tooth is not hidden bytoothpaste and the like and there are almost no stain on the teeth; (2)a second state in which the surface of the tooth is slightly visible butthere is a substance such as toothpaste adhered to the tooth or in thepath that blocks the light in the portion where plaque and tartar areadhering; and (3) a third state in which the light receiving element 25is covered by toothpaste and the like. Thus, it is not automaticallyknown the exact reason that the amount of R light is less than or equalto the third threshold TH3 for a period of time equal to or greater thanthe fourth threshold TH4. However, the exact reason is not important inall embodiments.

In the first state, it is possible to exhibit the function of stainsensing on tooth because nothing is blocking the tooth. However, it isnot known if the low R light value is due to lack of stain on the toothor due to the tooth being blocked. In the second state and third state,it is not possible to exhibit a function of stain sensing of the toothbecause the tooth or a path from the light emitting element 24 toportions of the tooth with plaque thereon and back to the lightreceiving element 25 is blocked. Thus, when the determination of stepS19 is YES, by the process of step S20 being carried out (spraying fluidinto the mouth), the substance (i.e., toothpaste or the like) adheringto the tooth is removed, and when there is plaque or tartar, the plaqueor tartar can be exposed. In addition, by removing the substanceadhering to the tooth, detection of the R light can be satisfactorilycarried out.

After step S20, the controller 50 resets the R light non-detectioncounter (returns the counter value to the initial value of zero), andclears the time stored according to the count value of the R lightnon-detection counter (Step S21). After step S21, the process returns tostep S10, and the B light is emitted again at a predetermined timing.

When the determination of step S17 is NO, meaning that the amount of Rlight being detected is greater than the third threshold (i.e., there isa lot of plaque detected on the tooth), the controller 50 resets the Rlight non-detection counter (returns the counter value to the initialvalue of zero), and clears the time stored according to the count valueof the R light non-detection counter (Step S22). After that, thecontroller 50 calculates the amount of stain on the tooth based on thedetection signal of the light receiving element 25, and the amount ofstain calculated is notified from the notification unit 60 (Step S23).

After step S23, the controller 50 controls the valve 28 and pump 29 andsupplies water to the fluid conduit 27 from the tank 30 at a thirdsupply amount and a third pressure (third condition), and sprays theliquid from the tip end of the fluid conduit 27 (Step S24) through thehole 21 and into the user's mouth. After step S24, the process returnsto step S10, and the B light is emitted again at a predetermined timing.In certain embodiments, the third supply amount may be lower than thefirst and/or second supply amounts and the third pressure may be lowerthan the first and/or second pressures. However, the invention is not tobe so limited in all embodiments and the third supply amount and/or thethird pressure may be the same or greater than the first/second supplyamounts and/or the first/second pressures. Thus, variations in the exactsupply amounts during the various first, second, and third conditionsare possible and fall within the scope of the disclosure set forthherein.

As described above, in the electric toothbrush 100, when the timing ofthe determining of step S13 becomes YES, that is, when the state inwhich the amount of light of G light detected by the light receivingelement 26 is not more than the threshold TH1 for a time period that isnot less than the threshold TH2, the liquid is sprayed from the hole 21under the first condition. Thus, even in a state in which a tooth wherethe plurality of tooth cleaning elements 22 are applied is covered by asubstance such as toothpaste, it is possible to remove the substance bythe force of the liquid. Therefore, it is possible to expose plaque andtartar adhering to the tooth, and it is possible to carry out sensing ofthe stain amount of the tooth.

In addition, in the electric toothbrush 100, when the timing of thedetermining of step S19 becomes YES, that is, when the state in whichthe amount of light of R light detected by the light receiving element25 is not more than the threshold TH3 for a time period that is not lessthan the threshold TH4, the liquid is sprayed from the hole 21 under thesecond condition.

Thus, even in a state in which plaque and tartar is covered by asubstance such as toothpaste, it is possible to remove the substance bythe force of the liquid. Therefore, it is possible to expose plaque andtartar adhering to the tooth, and it is possible to carry out sensing ofthe stain amount of the tooth. In addition, even in a state in which thelight receiving element 25 is covered by a substance, it is possible toremove the substance by the liquid sprayed from the hole 21, and it ispossible to carry out sensing of the stain of the tooth. Thus, incertain embodiments the spray of liquid at steps S14 and S20 is forclearing a path from the light emitting element 24 to the tooth and thenfrom the tooth back to the light receiving element(s) 25, 26. Thus, thefirst and second spray conditions may be configured to ensure that thespray clears the path as disclosed herein.

In addition, in the electric toothbrush 100, when the amount of light ofR light exceeds threshold TH3, since the liquid is sprayed from the hole21 at step S24, it is possible to remove the plaque by the force of theliquid, and by combing with brushing by the tooth cleaning elements 22,it is possible to increase the plaque removal effect. Thus, in someembodiments the spray of liquid at Step S24 is for plaque and tartarremoval. Thus, the third spray condition may be configured to removeplaque and tartar from teeth (rather than clearing a path as with thespray of liquid at steps S14 and S20). Thus, different purposes for theliquid spray at Step 24 than at Steps 14 and 20 may require differentspray conditions (pressure, spray velocity, amount of liquid, etc.).

In addition, when the determination of the step S17 is NO, there arecases when the amount of light of the G light is not more than thethreshold TH1, or the tooth may be hidden by toothpaste and the like orthe toothpaste and the like may be adhered to the light receivingelement 26. It is possible to remove toothpaste and the like that isadhered to the tooth by the process of step S24, and it becomes easierto do better stain sensing. Thus, the spray at step S24 may be used as afallback spray step to ensure proper stain sensing in some embodiments.

Note that, the relationship between the threshold TH2 and the thresholdTH4 described in FIG. 4, is preferable such that threshold TH2<thresholdTH4. The state in which the amount of light of R light is not more thanthe threshold TH3, includes a state in which there is no more plaque asa result of brushing. Thus, when a state continues for a short time inwhich the amount of light of R light is not more than the threshold TH3,the spraying of the liquid is carried out, and in a state in which thereis almost no plaque adhering to the tooth and a state in which theplaque has been sufficiently reduced by the progression of brushing, thespray of the liquid is frequently carried out. Thus, in regards tothreshold TH4, it is preferable to keep the value larger than thresholdTH2. This will prevent a frequent spray even when the lower R lightvalue is due to there being low amounts of plaque on the teeth asopposed to it being due to the absence of a path for the light to travelfrom the light emitting element 24 to the tooth and back to the lightreceiving element 25.

On the other hand, the state in which the amount of light of G light isnot more than the threshold TH1, includes a state in which toothpasteand the like adheres to the brushing portions. In fact, a low amount ofG light almost always means that there is something blocking the line ofsight to the tooth. Thus, when this state is left alone for a long time,the sensing of plaque also becomes impossible because it is almost aguarantee that something is blocking the line of sight to the tooth.Therefore, concerning threshold TH2, it is preferable to keep the valuesmaller than threshold TH4.

As set forth above, in certain embodiments the purpose of the liquid instep S14 and step S20 may be to remove the substance blocking the lightadhering to the tooth or light receiving element. On the other hand, thepurpose of the liquid spray in step S24 may be to remove the plaqueadhering to the tooth. Thus, since the liquid spray in step S14 and stepS20 and the liquid spray in step S24 have different purposes, the sprayconditions of the liquid in the respective liquid sprays may bedifferent as described above, but the liquid spray of both may also becarried out by the same conditions.

In order to remove the toothpaste and the like, since a certain amountof liquid and pressure is necessary, as described by FIG. 4, the liquidspray in step S14 and step S20 and the liquid spray in step S24 may setdifferent conditions. However, the removal of the toothpaste and thelike is an operation not directly related to the brushing. Thus, in stepS14 and step S20, the liquid spray may be carried out with a largerliquid amount and higher pressure than that of step S24. However, thismay result in an uncomfortable feeling to the user. In order to reducethis uncomfortable feeling, in FIG. 4, the liquid spray in step S14 andstep S20 may be carried out according to a condition with a highersupply amount or pressure than the liquid spray in step S24. As notedabove, the third condition may be a condition that only reduces thesupply amount of liquid relative to the first and/or second conditions,or, may be a condition that only lowers the pressure in relative to thefirst and/or second conditions. The terms first, second, and thirdpreceding the term condition are merely intended to distinguish betweenthe conditions without requiring that the conditions be different. Thus,the first, second, and/or third conditions may be the same or differentin different embodiments.

In the process of step S24, since a stain of the tooth in step S23 issensed (step S17 is no, meaning that the amount of R light, which islight that reflects off of plaque or tartar on the tooth, is greaterthan the third threshold TH3), the spray conditions of the liquid may bedetermined according to the degree of stain sensed. For example, thelarger the stain, the larger the supply amount of the liquid and thehigher the pressure of the liquid. Thus, the controller 50 may determinethe exact amount of the stain based on the amount of the R lightreceived by the light receiving element 25, and alter the spraycondition (amount and pressure) accordingly. Thus, the amount of staincan be reduced efficiently.

In addition, since the removal of plaque itself is carried out by theoscillation of the plurality of tooth cleaning elements 22, the processof step S24 of FIG. 4 may be omitted in some embodiments. Thus, in someembodiments the spray of liquid may only be used to clear away thedentifrice or other substance so that the light can pass from the lightemitting element 24 to the tooth and from the tooth to the lightreceiving elements 25, 26, but not also for plaque and tartar removal.

In each of the processes of step S14, step S20, and step S24 illustratedin FIG. 4, the liquid is sprayed from the hole 21. In the exemplifiedembodiment, the spray direction of the liquid is substantially the sameas the pressing direction (first direction) in regards to the tooth ofthe brush unit 20 (i.e., perpendicular to the front surface 41 of thebrush unit 20). Therefore, when the liquid is sprayed from the hole 21,if the brush unit 20 oscillates in the second direction, the spray pathcould be blocked by the tooth cleaning elements 22 due to the incline ofthe tooth cleaning elements 22. Specifically, when the brush unit 20oscillates in the second direction (back-and-forth in a direction ofeither the opposing side edges of the brush unit 20 or the distal andproximal ends 20 of the brush unit 20), the tooth cleaning elements 22may bend naturally due to the speed of oscillation and theflexibility/flimsiness of the tooth cleaning elements 22. As a result,in certain embodiments there may be a loss of pressure of the liquidsprayed due to the liquid contacting the bent tooth cleaning elements 22before entering into the user's mouth. Thus, it is possible that thismay weaken the effect of the removal of toothpaste and the like, or theremoval of plaque. This same concern does not arise when the brush unit20 oscillates in the first direction or mode because the tooth cleaningelements 22 do not bend in a manner that would block the fluid spray inthis movement direction.

Therefore, in such embodiments the controller 50 may carry out only thefirst drive when carrying out each of the processes of step S14, stepS20, and step S24. Specifically, the controller 50 may only oscillatethe brush unit 20 in the first direction (perpendicular to the shaft ofthe motor and in the pressing direction of the tooth cleaning elements22) when the controller 50 is causing the liquid to be sprayed. By doingso, when the liquid is sprayed from the hole 21, the possibility of thespray path of the liquid being blocked by the tooth cleaning elements 22can be reduced. Thus, the possibility of weakening the effect of theremoval of toothpaste and the like and the removal of plaque is reduced.In various embodiments, when other than each of the processes of stepS14, step S20, and step S24 (i.e., when the fluid is not being sprayed),the controller 50 may carries out only the first drive, only the seconddrive, or a combination of the first drive and the second drive(alternating or the like).

In some embodiments, the controller 50, enabled to detect the brushpressure, may carry out the second drive when the brush pressure is highand may carry out the first drive when the brush pressure is low. Inaddition, the controller 50, enabled to detect the posture (orientationor location in the mouth) of the electric toothbrush 100, may selectwhether to carry out only the first drive, carry out only the seconddrive, or combine the first drive and the second drive, according to thedetected posture.

In addition, in FIGS. 1 to 3 it is made possible to oscillate the brushunit 20 in the first direction and the second direction due to theeccentric shaft 13 and the weight 14. However, the invention is not tobe so limited and the stem 11 and brush unit 20 may be in anyconfiguration that can integrally oscillate in the first direction andthe second direction. For example, the brush unit 20 may be one that canoscillate in the first direction and the second direction via sound waveoscillating. Thus, the eccentric shaft 13 and the weight 14 is just oneexample of a technique for oscillating the brush unit 20, and othertechniques are possible and fall within the scope of the presentinvention.

In addition, the electric toothbrush 100 may be a simple configurationthat can only oscillate the brush unit 20 mounted on the stem 11 in onedirection. In addition, the electric toothbrush 100 may have a rotatableconfiguration of the brush unit 20 in regards to the housing of thebrush unit 20 portion wherein the plurality of tooth cleaning elements22 are provided, and may be a configuration such that the brush unit 20is driven by the drive mechanism provided in the stem 11 which rotatesthis portion and carries out a tooth brushing operation.

FIG. 5 is a planar view illustrating a schematic configuration in whichthe electric toothbrush 200 that is a modification of the electrictoothbrush 100 illustrated in FIG. 1, is viewed from the brush pressingdirection. The electric toothbrush 200 is similar to the electrictoothbrush 100 except as described herein. The electric toothbrush 200is similarly numbered to the electric toothbrush 100 except that the200-series of numbers is used. Thus, for components of the electrictoothbrush 200 that are similarly numbered to components of the electrictoothbrush 100, it should be appreciated that the description of thatcomponent above with reference to the electric toothbrush 100 isapplicable.

The electric toothbrush 200 is the same configuration as the electrictoothbrush 100, except that the light receiving element 26 is removed.Thus, the electric toothbrush 200 includes a light emitting element 224and a light receiving element 225 that receives R light, but not also alight receiving element that includes G light. All other features of theelectric toothbrush 200 are identical to the electric toothbrush 100 andthus the description above is applicable. The electric toothbrush 200 iscapable of function similar to the electric toothbrush 100 despite theomission of the light receiving element receiving G light.

FIG. 6 is a flowchart for describing an operation of the electrictoothbrush 200 illustrated in FIG. 5. In FIG. 6, the same stepsdescribed in FIG. 4 are denoted by the same reference numerals and thatdescription of FIG. 4 above may be referred to for clarity as to what isshown in FIG. 6. The controller (not shown with regard to thisembodiment, but the controller 50 described above is applicable) of theelectric toothbrush 200 carries out the steps of step S17 and subsequentsteps described in FIG. 4, after emitting the B light in step S10.Basically, in this embodiment steps S11 through S16 from the previousembodiment are omitted because they relate to the receiving of G light,which does not occur in this embodiment. However, step S10 and S17through S24 do occur in an identical manner to the previous embodiment.In the interest of brevity, these steps will not be described againhere, it being understood that the description above with reference toFIG. 4 is applicable.

As described above, even in a configuration without the light receivingelement that receives G light, by the liquid being sprayed from the hole221 when a state in which the amount of light of R light detected by thelight receiving element 25 is not more than the threshold TH3 for a timeperiod that is not less than threshold TH4, it is possible to reduce thestate in which sensing of the stain amount of the tooth cannot becarried out. Specifically, the liquid spray at step S20 will still clearthe path for the light to be emitted onto the tooth and reflected backto the light receiving element 25.

Note that in the electric toothbrush 100 of FIG. 1, regardless of theamount of light of R light, the liquid is sprayed from the hole 21 whenthe state in which the amount of light of G light is not more than thethreshold TH1 for a time period that is not less than the threshold TH2.Thus, in the previously described embodiment of the electric toothbrush100, not only is the R light, but the amount of light of G light is alsomonitored, and controlling the spray timing of the liquid is based onthe size of the amount of G light and/or the amount of R light.

FIG. 7 is a planar view illustrating a schematic configuration in whichthe electric toothbrush 300 that is a modification of the electrictoothbrush 100 illustrated in FIG. 1, is viewed from the brush pressingdirection. The electric toothbrush 300 is similar to the electrictoothbrush 100 except as described herein. The electric toothbrush 300is similarly numbered to the electric toothbrush 100 except that the300-series of numbers is used. Thus, for components of the electrictoothbrush 300 that are similarly numbered to components of the electrictoothbrush 100, it should be appreciated that the description of thatcomponent above with reference to the electric toothbrush 100 isapplicable.

The electric toothbrush 300 is the same configuration as the electrictoothbrush 100, except that the position of the hole 321 through whichthe liquid is sprayed is different. Specifically, in this embodiment twoholes 321 are provided in the brush unit 320 of the electric toothbrush300. The two holes 321 are disposed to be across from each other in aregion formed by the plurality of brushes 322. Stated another way,rather than being located within the field of tooth cleaning elements322 and surrounded by the tooth cleaning elements 322, the two holes 321are positioned closer to the lateral sides of the brush unit 320 thanthe outermost ones of the tooth cleaning elements 322. According to thisconfiguration, the number of tooth cleaning elements 322 can beincreased compared to the electric toothbrush 100 because the holes 321are external to the field of the tooth cleaning elements 322 rather thanbeing centrally located within the field of the tooth cleaning elements322.

In the electric toothbrushes 100 and 300, a light receiving element 25,325 is used as a reflected light detecting module for detecting the Rlight that is the reflected light of the B light, and a light receivingelement 26, 326 is used as a reflected light detecting module fordetecting the G light that is the reflected light of the B light.Instead of the light receiving element 25, 325 and the light receivingelement 26, 326, an imaging element disposed in a two-dimensional shape(for example, a staggered shape) with a photoelectric conversion elementfor detecting R light, and a photoelectric conversion element fordetecting G light, may be used as the reflected light detecting modulefor detecting the reflected light of the B light.

When using an imaging device, among the output signals of the photoelectric conversion element group for detecting R light (G light), thetotal number of output signals that has a minimum detection signal orabove, may be treated as the amount of light of R light (G light). Inaddition, among the output signals of the photo electric conversionelement group for detecting R light (G light), the cumulative value ofoutput signals that has a minimum detection signal or above, may betreated as the amount of light of R light (G light).

FIG. 8 is a planar view illustrating a schematic configuration in whichthe electric toothbrush 400 that is a modification of the electrictoothbrush 200 illustrated in FIG. 5, is viewed from the brush pressingdirection. The electric toothbrush 400 is similar to the electrictoothbrush 200 except as described herein. The electric toothbrush 400is similarly numbered to the electric toothbrush 200 except that the400-series of numbers is used. For components of the electric toothbrush400 that are similarly numbered to components of the electric toothbrush100, it should be appreciated that the description of that componentabove with reference to the electric toothbrush 100 is applicable.

The electric toothbrush 400 is the same configuration as the electrictoothbrush 200, except with respect to the positioning of the lightemitting element 424 and the light receiving element 425 in the stem411. Furthermore, the position of the transparent window 423 formed inthe housing of the brush unit 420 in regards to the light emittingelement 424 and the light receiving element 425 is different.

The light emitting element 424 and the light receiving element 425 builtinto the stem 411 of the electric toothbrush 400, as viewed from thebrush pressing direction, are disposed so as to be on either side of thehole 421. Then, the transparent window 423 is formed in the housing ofthe brush unit 420 opposing the light emitting element 424 and the lightreceiving element 425

The operation of the electric toothbrush 400 is the same as the electrictoothbrush 200. According to the electric toothbrush 400, since thetransparent window 423 opposite of the light receiving element 425 andthe light emitting element 424 is close to the hole 421, the substanceadhering to the transparent window 423 can be effectively removed by theliquid sprayed from the hole 421.

In the electric toothbrushes 100 to 400, a light emitting element and alight receiving element included in the light detecting part, isprovided in the stem 11, 211, 311, but the light emitting module and thereflected light detecting module may be provided on the outside surfaceof the housing (the same surface formed by the tooth cleaning elements22, 622, 322, 422) of the brush unit 20, 220 320, 420. In this case, thelight emitting element functions as the light emitting module. Accordingto the electric toothbrushes 100 to 400, it is possible to suppress themanufacturing cost of the consumable brush unit 20, 220 320, 420 as muchas possible.

In the embodiments described above, the configuration for spraying aliquid from the hole 21, 221, 321, 421 has been described, but it may beconfigured to spray a gas such as air from the hole 21, 221, 321, 421instead of a liquid. Thus, in certain embodiments the material beingsprayed is referred to herein as a fluid, which includes a liquid and agas. In certain embodiments, in the electric toothbrushes 100 to 400, ifthere is no liquid in the tank 30, air can be sprayed from the hole 21,221, 321, 421. Thus, the electric toothbrush 100 to 400 may beconfigured so that a fluid including a liquid or a gas can be sprayedfrom the hole 21, 221, 321, 421. In some embodiments, the electrictoothbrushes 100 to 400 may be configured to spray only a liquid or onlya gas, and in other embodiments the electric toothbrushes 100 to 400 maybe configured to spray either a liquid or a gas depending on what is inthe tank 30. In certain embodiments, using a liquid as the fluid ispreferred as it is more effective at plaque removal and the removal oftoothpaste as described herein.

FIG. 9 is a plan view illustrating a schematic configuration seen fromthe brush pressing direction of an electric toothbrush 500 that is amodified example of the electric toothbrush 100 illustrated in FIG. 1.The electric toothbrush 500 is similar to the electric toothbrush 100except as described herein. The electric toothbrush 500 is similarlynumbered to the electric toothbrush 100 except that the 500-series ofnumbers is used. Thus, for components of the electric toothbrush 500that are similarly numbered to components of the electric toothbrush100, it should be appreciated that the description of that componentabove with reference to the electric toothbrush 100 is applicable.

The electric toothbrush 500 is the same configuration as the electrictoothbrush 100 except that the transparent window 23, the transparentwindow 23 a, the light emitting element 24, the light receiving element25, the light receiving element 26, and the substrate 15 are removedfrom the device. Thus, the electric toothbrush 500 includes a hole 521and the other components necessary for spraying a fluid through the hole521, but the light emitting and light receiving elements 24, 25, 26 andassociated other components are omitted. In the electric toothbrush 500,spraying of a fluid from the hole 521 is performed for the removal ofplaque, food remains, or the like in the mouth. The controller of theelectric toothbrush 500 controls the valve and the pump at apredetermined timing, or a timing indicated by the user of the electrictoothbrush 500, and performs a control spraying a fluid from the hole21. The controller of the electric toothbrush 500 controls the motor Min the same way as the controller 50 of the electric toothbrush 100 anddrives the brush unit 20. It is noted that the controller, valve, pump,tank, and fluid conduit are not specifically shown in FIG. 9, but thedetails of those components are illustrated in FIGS. 2 and 3 anddescribed above are applicable.

When the power of the electric toothbrush 500 is on and the brushingmanipulation starts, the controller of the electric toothbrush 500starts the control alternately performing the first driving and thesecond driving. By this, the brush unit 520 pressed to the toothalternately repeats the oscillation in the first direction and theoscillation in the second direction, and the plaque adhering to thetooth is removed by the tooth cleaning elements 522.

The controller of the electric toothbrush 500 pauses alternatelyperforming the first driving and the second driving at a predeterminedtiming, or when the fluid sprays indicated by the user of the electrictoothbrush 500 after brushing starts, and performs only the firstdriving. Furthermore, the controller controls the valve and the pump,supplies liquid or gas from inside of the tank to the fluid conduit at aspecified supply amount and a specified pressure, and sprays a fluidfrom the tip end of the fluid conduit.

The controller of the electric toothbrush 500 controls the motor M andrestarts the control alternately performing the first driving and thesecond driving when the spraying of the fluid ends. Hereafter, thecontroller performs the same action at a predetermined timing, or at afluid spraying indicated by the user. Thus, as described briefly above,in this embodiment the electric toothbrush 400 (or the brush unit 520thereof) only oscillates in the first driving when the fluid is beingsprayed. This is because in the second driving, the flexibility/movementof the tooth cleaning elements 522 causes the tooth cleaning elements522 to block the fluid spray, which reduces its positive effects. Byonly oscillating in the first driving when fluid is being sprayed, itcan be ensured that the fluid reaches its intended target because it isnot blocked by the tooth cleaning elements 522.

As above, according to the electric toothbrush 500, as was describedbefore, the pressure loss of the fluid can be made to the lowest limitand the removal effect of plaque or the like can be enhanced when thefluid is sprayed from the hole 521 since only the first driving isperformed. On the other hand, plaque can be effectively removed when thefluid is not sprayed from the hole 521 since the first driving and thesecond driving are performed alternately.

Note that when the fluid is not sprayed from the hole 521, thecontroller may perform only the first driving, perform only the seconddriving, or the like, rather than alternating between the first drivingand the second driving (or the first and second modes). For example, thebrush pressure may be made able to be detected, and the controllerperforms only the second driving when the brush pressure is high, andperforms only the first driving when the brush pressure is low.Furthermore, the posture, orientation, or location of the electrictoothbrush 500 may be made able to be detected, and the controller maychoose whether to perform only the first driving, perform only thesecond driving, or perform the first driving and the second driving incombination based on the detected posture.

FIG. 10 is a planar drawing showing a simplified configuration of anelectric toothbrush 600 from the direction of pressing, for describingan embodiment of the present invention. The electric toothbrush 600 issimilar to the electric toothbrush 200 in that it only includes one,rather than two, light receiving elements. Nonetheless, the full detailsof the electric toothbrush 600 will be provided below. The electrictoothbrush 600 comprises a gripping portion 610 containing a battery andan electric control system in its interior, a main body having a stem611 fixed to the gripping portion 610, and a brush unit 620 that can beattached to and removed from to the stem 611. For the details of thebrush unit 620 and its coupling to the stem 611, the description withregard to FIGS. 1 and 2 above is applicable.

The brush unit 620 comprises a plurality of tooth cleaning elements 622extending from the front surface thereof, a hole 621 formed into thefront surface for spraying liquid, and a transparent window 623 so thatlight from a light emitting element 624 can pass therethrough andreflected light can pass therethrough back to a light receiving element625. For the specific details of the tooth cleaning elements 622, thedescription of the tooth cleaning elements 622 above with regard toFIGS. 1 and 2 is applicable.

In this embodiment, the hole 621 is disposed in a region surrounded bythe tooth cleaning elements 622 similar to the configuration of FIGS. 1and 2, although the invention is not to be so limited and the hole 621may be positioned at other locations along the brush unit 620. Thetransparent window 623 is located similarly to the location describedabove with regard to FIGS. 1 and 2, although it can be placed at otherlocations in other embodiments. The transparent window 623 is formed byfitting a translucent member such as a transparent resin or transparentglass or the like into a hole provided on the housing of the brush unit620. The transparent window 623 is disposed closer to the distal end ofthe brush unit 620 than the region formed by the plurality of toothcleaning elements 622 and it is on the surface of the brush unit 620from which the plurality of tooth cleaning elements 622 extend (i.e.,the front surface). The position of the transparent window 623 is oneexample, and the invention is not limited to the position shown in FIG.10. The transparent window 623 should be disposed to allow lightemission in the direction that the tooth cleaning elements 622 extends,from the plane on which the tooth cleaning elements 622 is formed.

FIG. 11 is a cross-sectional pattern diagram of line A-A of the electrictoothbrush 600 shown in FIG. 10. The brush unit 620 is composed of atube-shaped housing closed on the front end part having a hollow part620 a. The brush unit 620 is installed on the main body by positioningthe stem 611 within the hollow part 620 a. The stem 611 is composed of atube-shaped housing with the front end part (the end part opposite theside of the gripping portion 610) closed. The stem 611 comprises abearing 612 formed on the front end of the interior, an eccentric shaft613, one end of which is inserted into the bearing 612, a weight 614, asubstrate 615, a light emitting element 624 formed on the substrate 615,a light receiving element 625 formed on the substrate 615 (see FIG. 10),a transparent window 623 a provided on the housing, and a fluid conduit627. The features that are numbered similarly to the features of theelectric toothbrush 100 in FIGS. 1 and 2 have similar structure andfunction, and thus the description of those features provided above withreference to FIGS. 1 and 2 is applicable to this embodiment as wellexcept where it conflicts with the disclosure set forth below.

The gripping portion 610 comprises a valve 628 connected to the fluidconduit 627 that extends from inside the stem 611, a pump 629 connectedto the valve 628, a tank 630 connected to the pump 629, a liquid supplyopening 631 for pouring liquid in the tank 630, a cap 632 for closingthe liquid supply opening 631, and a motor M linked to the eccentricshaft 613 in the stem 611. The other end of the eccentric shaft 613 islinked to the rotating shaft of the motor M contained in the grippingportion 610. The eccentric shaft 613 rotates by the rotation of therotating shaft of the motor M.

The weight 614 is fixed to the eccentric shaft 613 in the vicinity ofthe bearing 612. The center of gravity of the eccentric shaft 613 isoffset from the center of rotation by the weight 614. Note that a minuteclearance is provided between the bearing 612 and the eccentric shaft613. The eccentric shaft 613 rotates with the rotation of the rotatingshaft of the motor M, but because the center of gravity of the eccentricshaft 613 is offset by the weight 614, it performs a movement as if itgyrates around the center of rotation. Thus, the tip of the eccentricshaft 613 repeatedly collides relative to the inner wall of the bearing612, thereby causing the stem 611 and the brush unit 620 installedthereon to oscillate at high speed. In this manner, with the driveprinciple of the oscillation of the brush unit 620 due to the gyrationmovement of the eccentric shaft 613, the brush unit 620 can oscillatetwo-dimensionally in a plane perpendicular to the rotating shaft of themotor M.

The electric toothbrush 600 can switch between the operation wherein thestem 611 and the brush unit 620 are oscillated in a first mode in thedirection of pressing the tooth cleaning elements 622 and the operationwherein the stem 611 and the brush unit 620 are made to oscillate in asecond mode in a direction intersecting (preferably perpendicular to)the direction of pressing the tooth cleaning elements 622 (which may bein a plane perpendicular to the rotating shaft of the motor M). Notethat the direction of pressing the tooth cleaning elements 622 is thesame as the direction that each tooth cleaning elements 622 extends.Also, the direction of pressing the tooth cleaning elements 622 isperpendicular to the direction in which the rotating shaft of the motorM extends.

As shown in FIG. 11, in the housing of the stem 611, a transparentwindow 623 a that is substantially the same size as the transparentwindow 623 is formed on the portion opposing the transparent window 623of the housing of the brush unit 620. The transparent window 623 a isformed by fitting a translucent member such as a transparent resin or atransparent glass in the hole provided on the housing of the stem 611.The light emitting element 624 and the light receiving element 625illustrated in FIG. 10 are disposed on the substrate 615 positionedopposing the transparent window 623 a.

The light emitting element 624 is configured as a LED (Light-emitteddiode) or laser diode or the like. As for the light emitting element624, something that emits light in the blue wavelength region (referredto herein below as B light) necessary for detecting plaque, which is theobject subject to detection, is used. The B light emitted from the lightemitting element 624 passes through the transparent window 623 a and thetransparent window 623 and is emitted to the exterior of the brush unit620. The light emitting element 624, the transparent window 623 a, andthe transparent window 623 function as the light emitting module foremitting light from the brush unit 620.

The light receiving element 625 is configured as a photoelectricconversion element, such as a photodiode or the like, for convertinglight into an electric signal. The light receiving element 625 isconfigured from a photoelectric conversion element that detects light inthe red wavelength region (referred to herein below as R light) andoutputs a signal according to the amount of detected light. The lightreceiving element 625 is configured as a combination of a color filterthat transmits R light and a photodiode having sensitivity to visiblelight, a photodiode that can detect only R light, or the like.

When B light is emitted onto plaque adhered to a tooth, R light isexcited in the plaque. That is, R light is generated as reflected lightof the B light. The light receiving element 625 is provided fordetecting the R light obtained from the B light emitted from the lightemitting element 624 reflecting from the plaque. Thus, the lightreceiving element 625 functions as a reflected light detector fordetecting the R light that is reflected light of the B light emittedfrom the light emitting module. This concept has been described indetail above with reference to FIGS. 1-4 and should be readilyunderstood at this point.

The substrate 615 has a wire connection electrically connecting to thelight emitting element 624 and the light receiving element 625, and, forexample, a flexible substrate is used. The substrate 615 extends intothe gripping portion 610, and the wire connections formed on thesubstrate 615 are electrically connected to a controller 650 containedin the gripping portion 610 that is described later.

The tank 630 holds liquid inserted via the liquid supply opening 631.The liquid may be, for example, water, a cleansing liquid having aplaque breakdown effect, mouthwash, another type of oral care agent, orthe like. Although described herein as being a liquid, the material inthe tank 630 may be a fluid, which can include gases such as air inother embodiments.

The pump 629 sucks up the liquid held in the tank 630 and supplies it tothe valve 628. The valve 628 is coupled to the base end of the fluidconduit 627 extending from inside the stem 611, and controls the supplyamount and supply pressure of the liquid supplied to the fluid conduit627, as well as the supply timing of liquid to the fluid conduit 627.

The fluid conduit 627 is configured as a pipe-shaped member that canpass liquid therethrough. Within the housing of the stem 611, a hole 621a is provided on the portion opposing the hole 621 of the brush unit620. The front end of the fluid conduit 627 is fitted in the hole 621 a.By this configuration, the liquid sprayed from the front end of thefluid conduit 627 passes through the hole part 621 of the brush unit 620and is sprayed to the exterior of the brush unit 620.

The pump 629, the valve 628, the fluid conduit 627, the hole 621 a, andthe hole 621 function as the fluid spray module for spraying fluid fromthe brush unit 620. The spray direction of the liquid sprayed from thebrush unit 620 can be changed by changing the cross-sectional shape ofthe hole 621. The spray direction is preferably a direction such thatthe angle formed with the direction of pressing the tooth cleaningelements 622 is less than 90 degrees, and it is particularly preferablefor it to be the same as the direction of pressing the tooth cleaningelements 622 (the direction that the tooth cleaning elements 622extends).

FIG. 12 is a block diagram showing the internal configuration of themain body of the electric toothbrush 600 shown in FIG. 10. The main bodyof the electric toothbrush 600 is composed of the motor M, anotification part 660, the controller 650, the pump 629, and the valve628. As shown in FIG. 12, each of the valve 628, the pump 629, thenotification unit 660, the motor M, the light emitting element 624, andthe light receiving element 625 is operably coupled to the controller650. This enables the controller 650 to communicate with each of thesecomponents to provide instructions to or receive data from thesecomponents to achieve appropriate function and operation of the electrictoothbrush 600 similar to that which has been described above withreference to FIGS. 1-4.

The controller 650 functions as a drive module selectively performing afirst drive for oscillating the brush unit 620 in the direction ofpressing the tooth cleaning elements 622 which is a first direction, anda second drive for oscillating the brush unit 620 in a second direction(here, the direction intersecting the direction of pressing the toothcleaning elements 622 within the plane perpendicular to the rotatingshaft of the motor M) that is different from the first direction. Notethat the configuration may have the controller 650 oscillate the brushunit 620 in a second direction that is an arbitrary direction (forexample, the direction in which the rotating shaft of the motor Mextends) within a plane perpendicular to the first direction. Thus,while the first direction may be up-and-down (away from and towards thefront surface of the brush unit 620), the second direction may beside-to-side between the opposing sides of the brush unit 620 orback-and-forth between the distal and proximal ends of the brush unit620. In some embodiments, the invention is not to be particularlylimited by the exact movement imparted by the first and seconddrives/modes/directions as long as they are different. In someembodiments, the controller 650 switches between the first drive and thesecond drive by changing the rotating speed of the rotating shaft of themotor M, although other techniques are possible to achieve this in otherembodiments.

The controller 650 alternatingly performs, for example, the first driveand the second drive. In this manner, by automatically switching theoscillation direction of the brush unit 620, because the tips of thehairs of the tooth cleaning elements 622 are applied to the area to betreated from a variety of angles, a superior plaque removal effect canbe obtained compared to unidirectional brushing.

The controller 650 drives the light emitting element 624 via thesubstrate 615, and performs control of B light emission from the lightemitting element 624. Furthermore, the controller 650 performs aplaque/tartar/stain detection process for detecting plaque/tartar/stainadhered to the teeth based on the reflected light detected by the lightreceiving element 625. The plaque detection process is performed by theknown method based on the amount of light of R light (detection signallevel) detected at the light receiving element 625. In this regard, thecontroller 650 functions as a plaque detector.

The controller 650 controls the liquid spray timing from the hole 621based on the plaque detection results. In this role, the controller 650functions as a fluid spray controller.

The notification part 660 performs notification of the plaque levels tothe user of the electric toothbrush 600 by using a device such as aspeaker, LED, or the like. The notification part 660 follows thecommands from the controller 650 and performs notification to the userby playing a sound or lighting an LED. The content of the notificationis set to be the amount of plaque calculated by the controller 650. Forexample, the notification part 660 may light the LED a green color whenin a state of having a very small amount of plaque, and light the LED ared color when in a state of having a large amount of plaque or the liketo notify of the amount of plaque and support effective brushing of theteeth. Of course, these colors are merely exemplary and are notintending to be limiting in any way. In some embodiments, the LED maylight up only when the plaque levels are deemed sufficiently high (i.e.,higher than a threshold value) but not also when the plaque levels arelow.

FIG. 13 is a flow chart for describing the operation of the electrictoothbrush 600 shown in FIGS. 10 and 11. When the power of the electrictoothbrush 600 is turned on and the brushing start operation isperformed, the controller 650 starts the drive of alternatinglyperforming the first drive and the second drive (step S1). This causesthe brush unit 620, which is pressed against the teeth, to alternatinglyrepeat oscillation in the first direction and oscillation in the seconddirection, and plaque adhered to the teeth is removed by the toothcleaning elements 622. The controller 650 may drive the brush unit 620to alternate the oscillation types (first drive and second drive) basedon a preset time, based on orientation of the brush unit 620 in themouth, based on brushing pressure, or the like. Furthermore, in someembodiments the controller 650 may only drive one type of oscillationrather than two.

In some embodiments, the controller 650 causes the light emittingelement 624 to emit light at a predetermined timing while alternatinglyperforming the first drive and the second drive. As a result, the Blight emitted from the light emitting element 624 is emitted through thetransparent window 623 to the exterior of the brush unit 620 (step S2).The controller 650 acquires the output signal of the light receivingelement 625 immediately following light emission from the light emittingelement 624. Specifically, the light receiving element 625 essentiallyimmediately receives the reflected R light upon the B light reflectingoff of plaque on the tooth, and data indicative of the amount of R lightis transmitted to the controller 650 for processing. Thus, thecontroller 650 detects the amount of plaque adhered to the teeth (stepS3) based on the amount of light of R light detected by the lightreceiving element 625 (the detection signal level of the light receivingelement 625).

The controller 650 stops driving/oscillating the brush unit 620 thefirst drive and drives the brush unit 620 with only the second drive(step S5) when the amount of plaque calculated by the plaque detectionprocess exceeds a threshold and it is determined that there is plaque(step S4: YES). The controller 650 moves process to step S8 if theamount of plaque calculated by the plaque detection process is belowthreshold and it is determined that there is no plaque (step S4: NO).

In step S5, with the brush unit 620 in a condition such that it is beingdriven in the second drive, the controller 650 controls the valve 628and the pump 629, supplies the liquid in the tank 630 to the fluidconduit 627 at a predetermined supply amount and predetermined pressure,and sprays liquid from the front tip of the fluid conduit 627 (step S6).The liquid is preferably sprayed into the user's mouth, and morepreferably onto the user's teeth, to assist in plaque removal. After theliquid is sprayed for an adequate and pre-determined period of time, thecontroller 650 closes the valve 628 and stops the spraying of theliquid. The pre-determined period of time may change in some embodimentsbased on the amount of plaque detected in step S4. When the controller650 closes the valve 628 and finishes the spraying of the liquid, itresumes driving by alternatingly performing the first drive and thesecond drive (step S7).

After step S7, the controller 650 finishes the brushing operation if apredetermined amount of time has passed since the start of the brushingoperation (step S8: YES). On the other hand, if a predetermined amountof time has not passed since the start of the brushing operation (stepS8: NO), the controller 650 returns processes to step S2.

As described above, the electric toothbrush 600 sprays liquid from thehole 621 when the amount of plaque exceeds a threshold. Also, while thisliquid is being sprayed, the brush unit 620 only oscillates in thesecond direction. In a state such that the plurality of the toothcleaning elements 622 are applied to the surface of the teeth duringteeth cleaning, oscillating the brush unit 620 in the second directionmakes it difficult for the liquid sprayed from the hole 621 to leakoutside the gaps between each tooth cleaning elements 622. Specifically,in the second direction the brush unit 620 oscillates side-to-side orback-and-forth (the details of which have been described above), whichcauses the tooth cleaning elements 622 to bend/flex and block the flowpath of the liquid as it exits through the hole 621. Thus, byoscillating the brush unit 620 in the second direction during the liquidspraying action, the liquid is retained by/between the plurality of thetooth cleaning elements 622, and the liquid oscillates insynchronization with the oscillation of the brush unit 620. Thus, theplaque removal effect can be heightened by removing the plaque adheredto the teeth with the oscillating liquid and the oscillating brush unit620.

There are several different liquids that may be sprayed onto the teethto provide a benefit when used with the electric toothbrush 600. Inparticular, as for the liquid put into the tank 630, when using a liquidhaving an effect of breaking up plaque, having this liquid be retainedin the gaps between the tooth and the plurality of tooth cleaningelements 622, the breakup of plaque adhered to the tooth can behastened, and the plaque removal effect is heightened. Also, as for theliquid put into the tank 630, when using a liquid having an effect ofadhering to plaque and strengthening R light reflection, the plaquedetection accuracy in the following plaque detection process can beheightened. Thus, two non-limiting examples for the liquid in the tank630 includes a liquid with plaque breakup characteristics and a liquidwith plaque adhering and R light reflection strengtheningcharacteristics may be used. Of course, other liquids including thosedescribed throughout this document may also be used.

Note that the controller 650 may perform only the first drive or performonly the second drive while fluid is not being sprayed from the hole621. For example, it could be made to be able to detect brushingpressure, and the controller 650 could perform the second drive when thebrush pressure is high and perform the first drive when the brushpressure is low. Thus, there are many variations available and thecontroller 650 need not only alternate between the first and seconddrives, but rather may provide the best drive for a given circumstance.Also, in some embodiments the controller 650 could be made to detect theorientation of the electric toothbrush 600, so that the controller 650may select whether to perform only the first drive, perform only thesecond drive, or perform a combination of the first drive and the seconddrive according to the detected orientation.

In certain embodiments, the controller 650 may identify the type ofliquid stored in the tank 630, and perform the processes shown in FIG.13 only when the type of liquid identified is a liquid other than water,and when the type of liquid identified is water, to perform a processthat does not particularly limit the selection of the drive method instep S5 of FIG. 13.

For example, a button corresponding to the type of liquid may beprovided on the gripping portion 610. The controller 650 identifies thetype of liquid by which button is pressed. Alternatively, the tank 630can be made a removable and attachable cartridge, and a tag withidentification information is provided on the cartridge. Then, thecontroller 650 identifies the type of liquid by reading theidentification information from the tag on the cartridge installed onthe gripping portion 610. In this case, the controller 650 functions asa liquid identifying part. Many other techniques are possible to enablethe controller 650 to determine what substance is contained within thetank 630 so that the controller 650 may alter its function based on theparticular substance contained in the tank 630.

When the liquid sprayed from the hole 621 is water, plaque removaleffect is obtained by having the water retained between the plurality oftooth cleaning elements 622. However, the plaque removal effect isbigger when the liquid sprayed from the hole 621 is a liquid other thanwater (an oral cleansing liquid or the like having a plaque breakupeffect). Also, it is thought that when the liquid sprayed from the hole621 is water, the plaque removal effect may be larger if the water isapplied to the teeth with some force, more than retaining it between theplurality of tooth cleaning elements 622.

From these circumstances, it is best for the controller 650 to performcontrol that retains the liquid between the plurality of tooth cleaningelements 622 as in FIG. 13 to maximize the plaque removal effect, if theliquid in the tank 630 is a liquid other than water. Also, when theliquid is water, it is good for the controller 650 to perform only thefirst drive for oscillating the brush unit 620 in the first directionand to stop the second drive when liquid is being sprayed so that thewater is not retained between the plurality of tooth cleaning elements622 but is applied to teeth with some force in order to maximize theplaque removal effect when the liquid in the tank 630 is water. Thisconfiguration allows the optimum plaque removal effect to be obtainedaccording to the liquid sprayed from the hole 621.

On the electric toothbrush 600, the light element 624 may be provided onthe outer circumferential surface of the housing of the brush unit 620(the same surface on which the tooth cleaning elements 622 extend). Inthis case, the light emitting element 624 functions as a light emissionpart. Also, the light receiving element 625 may be provided on the outercircumferential surface of the housing of the brush unit 620. Accordingto the configuration of FIG. 10, the brush unit 620, which is aconsumable (i.e., replaceable and discardable) good, needs only thetransparent window 623 and the hole 621 added thereto relating to theready-made product, and manufacturing cost can be significantly reduced.Thus, it may be preferable to keep all of the electronic components as apart of the stem 611 or some other component that is not the brush unit620.

The second direction described above is preferably a directionperpendicular to the first direction. This makes the liquid sprayed fromthe hole 621 more easily retained between the plurality of toothcleaning elements 622, and further heightens the plaque removal effect.

Certain components are described herein as forming a module. The moduleis generally a collection of components that form a unit that isintended to perform a particular function. Although the descriptionprovides specific examples of components that form each module, theinvention is not to be so limited in all embodiments and less than allof the listed components may form the particular module being discussed.For example, in the description above the light emitting element 24, thetransparent window 23 a and the transparent window 23 may are describedas collectively forming a light emitting module for emitting light fromthe brush unit 20. However, the light emitting module may comprise onlythe light emitting element 24 but not also the transparent windows 23,23 a in some embodiments. Thus, it should be appreciated that althoughthe module is configured to perform a particular function, the inventionshould not be specifically limited by the exemplary embodimentsdescribed herein.

A program for executing each process carried out by the controller 50,650 of the present embodiment may be provided in a computer. Such aprogram is recorded in a non-transitory recording medium readable by acomputer.

Such a “computer readable recording medium” includes, for example, anoptical medium such as a compact disc-ROM (CD-ROM) or a magneticrecording medium such as a memory card. In addition, such program may beprovided by downloading via a network.

The embodiments disclosed herein are in all respects examples and are inno way considered to be limited thereto. The scope of the presentinvention is indicated by the scope of the patent claims and not by thedescriptions given above and is intended to include all alternativeswithin equivalent meaning and scope to the patent claims.

As described above, the following matters are disclosed in the presentspecification.

The disclosed electric toothbrush includes: a driving unit for driving abrush unit mounted on the main body; a light emitting module foremitting light from the brush unit; a reflected light detecting modulefor detecting reflected light of the light emitted from the lightemitting module; a stain sensing module for sensing a stain amount of atooth based on the reflected light detected by the reflected lightdetecting module; a fluid spraying module for spraying fluid from thebrush unit; and a fluid spray control unit for controlling the spraytiming of the fluid based on the amount of reflected light detected bythe reflected light detecting module.

In the disclosed electric toothbrush, the light emitting module emits ablue light, the reflected light detecting module detects individually ared light and a green light as the reflected light, the stain sensingmodule senses the stain amount of a tooth based on the red light, thefluid spray control unit sprays the fluid, in a first case in which theamount of red reflected light continues at not more than a firstthreshold and not less than a second threshold.

In the disclosed electric toothbrush, the fluid spray control unit,furthermore, sprays a fluid in a second case in a state in which theamount of red reflected light continues at not more than a thirdthreshold and not less than a fourth threshold of time.

In the disclosed electric toothbrush, the fluid spray control unit, whenthe amount of red reflected light exceeds the third threshold, sprays afluid in spray conditions differing from the spray conditions of thefluid in each of the first case and the second case.

In the disclosed electric toothbrush, the light emitting module emits ablue light, the reflected light detecting module detects a red light asthe reflected light, the stain sensing module senses the stain amount ofa tooth based on the red light, and the fluid spray control unit spraysthe fluid, in a third case in which the amount of red reflected lightcontinues at not more than a third threshold and not less than a fourththreshold of time.

In the disclosed electric toothbrush, the fluid spray control unit, whenthe amount of red reflected light exceeds the third threshold, sprays afluid in spray conditions differing from the spray conditions of thefluid in the third case.

The method for operating the disclosed electric toothbrush is a methodfor operating an electric toothbrush having a drive module for driving abrush unit mounted on the main body, including: a light emitting stepfor emitting light from the brush unit; a reflected light detecting stepfor detecting reflected light of the emitted light; a stain sensing stepfor sensing a stain amount of a tooth based on reflected light detectedby the reflected light detecting step; a fluid spray step for sprayingfluid from the brush unit; and a fluid spray control step forcontrolling the spray timing of the fluid based on the amount ofreflected light detected by the reflected light detecting step.

The disclosed electric toothbrush is provided with a driving portionthat performs a first driving that oscillates a brush unit installed ona main body portion in a first direction that is the pressing directionof a plurality of brushes provided on the brush unit and a seconddriving that oscillates the brush unit in a second direction that isdifferent from the first direction, and a fluid spraying unit thatsprays a fluid from the brush unit, and the driving portion performs thefirst driving while the fluid is sprayed from the fluid spraying unit.

The disclosed electric toothbrush is further provided with a lightemitting module that emits light from the brush unit, a reflected lightdetection portion that detects reflected light of the light emitted bythe light emitting module, a stain sensing portion that senses toothstain amount based on the reflected light detected by the reflectedlight detection portion, and a fluid spraying control unit that controlsthe spray timing of the fluid based on the light amount of the reflectedlight detected by the reflected light detection portion.

The disclosed electric toothbrush, wherein the light emitting moduleemits blue light, the reflected light detection portion individuallydetects red light and green light as reflected light, the stain sensingportion senses tooth stain amount based on the red light, and the fluidspraying control unit sprays the fluid in the first case where the statewhere the light amount of green reflected light at the first thresholdor below continues at the second threshold or above.

The disclosed electric toothbrush, wherein the fluid spraying controlunit further sprays the fluid in the second case where the state wherethe light amount of red reflected light at the third threshold or belowcontinues at the second threshold or above.

The disclosed electric toothbrush, wherein the fluid spraying controlunit sprays the fluid at spraying conditions different from the sprayingconditions of the fluid in the first and second case respectively, inthe case where the light amount of reflected red light exceeds the thirdthreshold.

The disclosed electric toothbrush, wherein the light emitting moduleemits blue light, the reflected light detection portion detects redlight as reflected light, the stain sensing portion senses tooth stainamount based on the red light, and the fluid spraying control unitsprays the fluid in the third case where the state where the lightamount of red reflected light at the third threshold or below continuesfor a time at the fourth threshold or above.

The disclosed electric toothbrush, wherein the fluid spraying controlunit sprays the fluid at spraying conditions different from the sprayingconditions in the third case, in the case where the light amount ofreflected red light exceeds the third threshold.

The disclosed electric toothbrush operation method is the electrictoothbrush operation method provided with a driving step that performsthe first driving that oscillates the brush unit installed on the mainbody portion of the electric toothbrush in the first direction which isthe pressing direction of the plurality of brushes provided on the brushunit and the second driving that oscillates the brush unit in the seconddirection that is different from the first direction, and a fluidspraying step that sprays the fluid from the brush unit, and the firstdriving is performed while the fluid sprays in the fluid spraying stepin the driving step.

The disclosed electric toothbrush is composed of a drive module forselectively performing a first drive for oscillating a brush unitinstalled on a main body in a first direction, which is the direction ofpressing a plurality of brushes provided on the brush unit and a seconddrive for oscillating the brush unit in a second direction, which isdifferent from the first direction; a light emitting module for emittinglight from the brush unit; a reflected light detector for detectingreflected light of the light emitted from the light emitting module; aplaque detector for detecting plaque based on the reflected lightdetected by the reflected light detector; a liquid spray part forspraying liquid from a portion surrounded by the plurality of brushesfrom the brush unit; and a liquid spray controller for controlling thespray timing of the liquid; wherein the liquid spray controller spraysthe liquid when the amount of plaque detected by the plaque detectorexceeds a threshold, and the drive module stops the first drive andperforms only the second drive while the liquid is being sprayed.

The disclosed electric toothbrush is further composed of a tank forstoring the liquid and a liquid identification part for identifying thetype of liquid stored in the tank, wherein the drive module implements atreatment such that the first drive is stopped and only the second driveis performed, only when the liquid identified by the liquididentification part is something other than water when the liquid isbeing sprayed.

The disclosed electric toothbrush includes things wherein the seconddirection is the direction perpendicular to the first direction.

The disclosed operating method of the electric toothbrush composed of alight emitting module for emitting light from a brush unit installed onthe electric toothbrush, a reflected light detector for detecting thereflected light of the light emitted from the light emitting module, anda liquid spray part for spraying liquid from a portion surrounded by theplurality of brushes from the brush unit, is composed of a drive stepfor selectively performing a first drive for oscillating a brush unitinstalled on a main body in a first direction, which is the direction ofpressing a plurality of brushes provided on the brush unit and a seconddrive for oscillating the brush unit in a second direction, which isdifferent from the first direction, a plaque detection step fordetecting plaque based on the reflected light detected by the reflectedlight detector, a liquid spray control step for spraying the liquid whenthe amount of plaque detected by the plaque detector exceeds athreshold, and within the drive step, the first drive is stopped andonly the second drive is performed while the liquid is being sprayed.

While the invention has been described with respect to specific examplesincluding presently preferred modes of carrying out the invention, thoseskilled in the art will appreciate that there are numerous variationsand permutations of the above described systems and techniques. It is tobe understood that other embodiments may be utilized and structural andfunctional modifications may be made without departing from the scope ofthe present invention. Thus, the spirit and scope of the inventionshould be construed broadly as set forth in the appended claims.

What is claimed is:
 1. An electric toothbrush, comprising: a drivingunit for driving a brush unit mounted on a main body; a light emittingmodule for emitting light from the brush unit; a reflected lightdetecting module for detecting reflected light of light emitted from thelight emitting module; a stain sensing module for sensing a stain amountof a tooth based on an amount of the reflected light detected by thereflected light detecting module; a fluid spraying module for sprayingfluid from the brush unit; and a fluid spray control unit forcontrolling spray timing of the fluid based on the amount of thereflected light detected by the reflected light detecting module;wherein the light emitting module emits a blue light; wherein thereflected light detecting module detects the reflected light as a redlight and a green light; wherein the stain sensing module senses thestain amount of the tooth based on the red light; and wherein the fluidspray control unit sprays the fluid under a first condition when anamount of the green light detected by the reflected light detectingmodule is equal to or less than a first threshold for a time period thatis greater than or equal to a second threshold.
 2. The electrictoothbrush according to claim 1, wherein the fluid spray control unitsprays the fluid under a second condition when an amount of the redlight detected by the reflected light detecting module is less than orequal to a third threshold for a time period that is greater than orequal to a fourth threshold.
 3. The electric toothbrush according toclaim 2, wherein when the amount of red light detected by the reflectedlight detecting module exceeds the third threshold, the fluid spraycontrol unit sprays the fluid under a third condition that differs fromeach of the first condition and the second condition.
 4. The electrictoothbrush according to claim 1, wherein: the light emitting moduleemits a blue light; the reflected light detecting module detects thereflected light as a red light; the stain sensing module senses thestain amount of the tooth based on the red light; and the fluid spraycontrol unit sprays the fluid under a second condition when an amount ofthe red light detected by the reflected light detecting module is notmore than a third threshold for a period of time that is not less than afourth threshold; and wherein when the amount of the red light detectedby the reflected light detecting module exceeds the third threshold, thefluid spray control unit sprays the fluid under a third condition thatdiffers from the second condition.
 5. An electric toothbrush,comprising: a body comprising a gripping part and a stem extending fromthe gripping part; a brush unit detachably coupled to the body, thebrush unit having an outer surface including a front surface having aplurality of tooth cleaning elements extending therefrom; a motorlocated within the body and operably coupled to an eccentric shaft tooscillate the brush unit; a light emitting element configured to emitlight from the brush unit; a light receiving element configured toreceive reflected light of the light emitted from the light emittingelement; a fluid dispensing system comprising a reservoir for storing afluid and a fluid conduit extending from the reservoir to an outlet; acontroller operably coupled to the motor, the light emitting element,the light receiving element, and the fluid dispensing system, thecontroller receiving data indicative of an amount of the reflected lightreceived by the light receiving element; wherein the controller controlsoperation of the fluid dispensing system based on the amount of thereflected light detected by the light receiving element; wherein thestem comprises an internal cavity, a first window that providesvisibility from an outer surface of the stem into the internal cavity ofthe stem, and a first opening extending from the outer surface of thestem to the internal cavity of the stem; and wherein the brush unitcomprises a second window that provides visibility into an interiorcavity of the brush unit, and a second opening extending from the outersurface of the brush unit to the interior cavity of the brush unit, thebrush unit coupled to the body so that the first and second windows andthe first and second openings are aligned, and wherein the outlet isformed by the first opening in the stem and the second opening in thebrush unit.
 6. The electric toothbrush according to claim 5 wherein thelight emitting element emits blue light towards a tooth, and wherein thereflected light comprises a green light component corresponding toportions of the blue light that reflects off of exposed portions of thetooth and an red light component corresponding to portions of the bluelight that reflects off of plaque on the tooth, and wherein the lightreceiving element transmits data to the controller indicative of anamount of the green light component and an amount of the red lightcomponent received by the light receiving element.
 7. The electrictoothbrush according to claim 6 wherein the controller is configured tooperate the fluid dispensing system to dispense the fluid under a firstcondition when the amount of the green light component received by thelight receiving element is less than or equal to a first threshold for aperiod of time that exceeds a second threshold.
 8. The electrictoothbrush according to claim 7 wherein the controller is configured tooperate the fluid dispensing system to dispense the fluid under a secondcondition when the amount of the red light component received by thelight receiving element is less than or equal to a third threshold for aperiod of time that exceeds a fourth threshold, and wherein thecontroller is configured to operate the fluid dispensing system todispense the fluid under a third condition when the amount of the redlight component received by the light receiving element is greater thanthe third threshold.
 9. The electric toothbrush according to claim 6wherein the controller is configured to operate the fluid dispensingsystem to dispense the fluid under a first condition when the amount ofthe green light component received by the light receiving element isless than or equal to a first threshold for a period of time thatexceeds a second threshold, wherein the controller is configured tooperate the fluid dispensing system to dispense the fluid under a secondcondition when the amount of the red light component received by thelight receiving element is less than or equal to a third threshold for aperiod of time that exceeds a fourth threshold, and wherein thecontroller is configured to operate the fluid dispensing system todispense the fluid under a third condition when the amount of the redlight component received by the light receiving element is greater thanthe third threshold.
 10. The electric toothbrush according to claim 9wherein the first and second conditions are the same and wherein thethird condition is different than the first and second conditions,wherein the first and second conditions comprise dispensing a firstamount of the fluid under a first pressure and wherein the thirdcondition comprises dispensing a second amount of the fluid under asecond pressure, at least one of the first and second amounts of fluidand the first and second pressures being different.
 11. The electrictoothbrush according to claim 9 wherein the fourth threshold is agreater period of time than the second threshold.
 12. An electrictoothbrush comprising: a body comprising a gripping part and a stemextending from the gripping part; a brush unit detachably coupled to thebody, the brush unit having an outer surface including a front surfacehaving a plurality of tooth cleaning elements extending therefrom; amotor located within the body and operably coupled to an eccentric shaftto oscillate the brush unit; a light emitting element configured to emitlight from the brush unit; a light receiving element configured toreceive reflected light of the light emitted from the light emittingelement; a fluid dispensing system comprising a reservoir for storing afluid and a fluid conduit extending from the reservoir to an outlet; acontroller operably coupled to the motor, the light emitting element,the light receiving element, and the fluid dispensing system, thecontroller receiving data indicative of an amount of the reflected lightreceived by the light receiving element; wherein the controller controlsoperation of the fluid dispensing system based on the amount of thereflected light detected by the light receiving element; wherein thestem comprises an internal cavity, a first window that providesvisibility from an outer surface of the stem into the internal cavity ofthe stem, and a first opening extending from the outer surface of thestem to the internal cavity of the stem; and wherein the light emittingelement and the light receiving element are located within the internalcavity of the stem in alignment with the first window of the stem.